diff --git a/src/plugins/comps/CompsManager.js b/src/plugins/comps/CompsManager.js
index 1d91c1b2fc..4b336a8fdd 100644
--- a/src/plugins/comps/CompsManager.js
+++ b/src/plugins/comps/CompsManager.js
@@ -11,6 +11,8 @@ export default class CompsManager extends EventEmitter {
   #loaded = false;
   #compositionLoaded = false;
   #telemetryProcessors = {};
+  // make id random 4 digit number
+  #id = Math.floor(Math.random() * 9000) + 1000;
 
   constructor(openmct, domainObject) {
     super();
@@ -70,7 +72,7 @@ export default class CompsManager extends EventEmitter {
       testValue: 0,
       timeMetaData
     });
-    this.emit('parametersUpdated', keyString);
+    this.emit('parameterAdded', this.#domainObject);
   }
 
   getParameters() {
@@ -104,7 +106,7 @@ export default class CompsManager extends EventEmitter {
       (parameter) => parameter.keyString === keyString
     );
     if (!parameterExists) {
-      this.#composition.remove(this.#telemetryObjects[keyString]);
+      this.emit('parameterRemoved', this.#domainObject);
     }
   }
 
@@ -129,20 +131,25 @@ export default class CompsManager extends EventEmitter {
     }
   }
 
-  startListeningToUnderlyingTelemetry() {
+  async startListeningToUnderlyingTelemetry() {
     console.debug('🎉 CompsManager: startListeningToUnderlyingTelemetry');
+    this.#loaded = false;
     Object.keys(this.#telemetryCollections).forEach((keyString) => {
       if (!this.#telemetryCollections[keyString].loaded) {
-        const specificTelemetryProcessor = this.#getTelemetryProcessor(keyString);
-        this.#telemetryCollections[keyString].on('add', specificTelemetryProcessor);
+        this.#telemetryCollections[keyString].on('add', this.#getTelemetryProcessor(keyString));
         this.#telemetryCollections[keyString].on('clear', this.clearData);
-        this.#telemetryCollections[keyString].load();
+        const telemetryLoadedPromise = this.#telemetryCollections[keyString].load();
+        this.#telemetryLoadedPromises.push(telemetryLoadedPromise);
       }
     });
+    await Promise.all(this.#telemetryLoadedPromises);
+    this.#telemetryLoadedPromises = [];
+    this.#loaded = true;
   }
 
   stopListeningToUnderlyingTelemetry() {
     console.debug('🔇 CompsManager: stopListeningToUnderlyingTelemetry');
+    this.#loaded = false;
     Object.keys(this.#telemetryCollections).forEach((keyString) => {
       const specificTelemetryProcessor = this.#telemetryProcessors[keyString];
       delete this.#telemetryProcessors[keyString];
@@ -209,11 +216,7 @@ export default class CompsManager extends EventEmitter {
     this.#telemetryCollections[keyString]?.destroy();
     delete this.#telemetryCollections[keyString];
     // remove all parameters that reference this telemetry object
-    this.#domainObject.configuration.comps.parameters =
-      this.#domainObject.configuration.comps.parameters.filter(
-        (parameter) => parameter.keyString !== keyString
-      );
-    this.emit('parametersUpdated', keyString);
+    this.deleteParameter(keyString);
   };
 
   requestUnderlyingTelemetry() {
diff --git a/src/plugins/comps/CompsMathWorker.js b/src/plugins/comps/CompsMathWorker.js
index 8ddea694dc..823e87c676 100644
--- a/src/plugins/comps/CompsMathWorker.js
+++ b/src/plugins/comps/CompsMathWorker.js
@@ -74,7 +74,7 @@ function calculate(dataFrame, parameters, expression) {
     otherParameters.forEach((parameter) => {
       const otherDataFrame = dataFrame[parameter.keyString];
       const otherTelemetry = otherDataFrame.get(referenceTime);
-      if (!otherTelemetry) {
+      if (otherTelemetry === undefined && otherTelemetry === null) {
         missingData = true;
         return;
       }
diff --git a/src/plugins/comps/CompsMetadataProvider.js b/src/plugins/comps/CompsMetadataProvider.js
index 6d859ef723..b12fc34ef2 100644
--- a/src/plugins/comps/CompsMetadataProvider.js
+++ b/src/plugins/comps/CompsMetadataProvider.js
@@ -34,7 +34,7 @@ export default class CompsMetadataProvider {
     return domainObject.type === 'comps';
   }
 
-  getDomains(domainObject) {
+  getDefaultDomains(domainObject) {
     return this.#openmct.time.getAllTimeSystems().map(function (ts, i) {
       return {
         key: ts.key,
@@ -56,7 +56,7 @@ export default class CompsMetadataProvider {
     // if there are any parameters, grab the first one's timeMetaData
     const timeMetaData = specificCompsManager?.getParameters()[0]?.timeMetaData;
     const metaDataToReturn = {
-      values: this.getDomains().concat([
+      values: [
         {
           key: 'compsOutput',
           source: 'compsOutput',
@@ -66,13 +66,13 @@ export default class CompsMetadataProvider {
             range: 1
           }
         }
-      ])
+      ]
     };
-    if (
-      timeMetaData &&
-      metaDataToReturn.values.some((metaDatum) => metaDatum.key === timeMetaData.key)
-    ) {
+    if (timeMetaData) {
       metaDataToReturn.values.push(timeMetaData);
+    } else {
+      const defaultDomains = this.getDefaultDomains(domainObject);
+      metaDataToReturn.values.push(...defaultDomains);
     }
     return metaDataToReturn;
   }
diff --git a/src/plugins/comps/CompsTelemetryProvider.js b/src/plugins/comps/CompsTelemetryProvider.js
index 345f050885..a6c6fa684b 100644
--- a/src/plugins/comps/CompsTelemetryProvider.js
+++ b/src/plugins/comps/CompsTelemetryProvider.js
@@ -29,6 +29,8 @@ export default class CompsTelemetryProvider {
   #lastUniqueID = 1;
   #requestPromises = {};
   #subscriptionCallbacks = {};
+  // id is random 4 digit number
+  #id = Math.floor(Math.random() * 9000) + 1000;
 
   constructor(openmct, compsManagerPool) {
     this.#openmct = openmct;
@@ -67,7 +69,11 @@ export default class CompsTelemetryProvider {
         const callbackID = this.#getCallbackID();
         const telemetryForComps = specificCompsManager.requestUnderlyingTelemetry();
         const expression = specificCompsManager.getExpression();
-        const parameters = specificCompsManager.getParameters();
+        const parameters = JSON.parse(JSON.stringify(specificCompsManager.getParameters()));
+        if (!expression || !parameters) {
+          resolve([]);
+          return;
+        }
         this.#requestPromises[callbackID] = { resolve, reject };
         const payload = {
           type: 'calculateRequest',
@@ -85,13 +91,16 @@ export default class CompsTelemetryProvider {
     });
   }
 
-  #computeOnNewTelemetry(specificCompsManager, newTelemetry, callbackID) {
+  #computeOnNewTelemetry(specificCompsManager, callbackID, newTelemetry) {
     if (!specificCompsManager.isReady()) {
       return;
     }
     const expression = specificCompsManager.getExpression();
     const telemetryForComps = specificCompsManager.getFullDataFrame(newTelemetry);
     const parameters = JSON.parse(JSON.stringify(specificCompsManager.getParameters()));
+    if (!expression || !parameters) {
+      return;
+    }
     const payload = {
       type: 'calculateSubscription',
       telemetryForComps,
@@ -111,12 +120,19 @@ export default class CompsTelemetryProvider {
     );
     const callbackID = this.#getCallbackID();
     this.#subscriptionCallbacks[callbackID] = callback;
-    specificCompsManager.on('underlyingTelemetryUpdated', (newTelemetry) => {
-      this.#computeOnNewTelemetry(specificCompsManager, newTelemetry, callbackID);
-    });
+    const boundComputeOnNewTelemetry = this.#computeOnNewTelemetry.bind(
+      this,
+      specificCompsManager,
+      callbackID
+    );
+    specificCompsManager.on('underlyingTelemetryUpdated', boundComputeOnNewTelemetry);
     specificCompsManager.startListeningToUnderlyingTelemetry();
+    console.debug(
+      `🧮 Comps Telemetry Provider: subscribed to comps. Now have ${Object.keys(this.#subscriptionCallbacks).length} listener`,
+      this.#subscriptionCallbacks
+    );
     return () => {
-      specificCompsManager.off('underlyingTelemetryUpdated', callback);
+      specificCompsManager.off('underlyingTelemetryUpdated', boundComputeOnNewTelemetry);
       delete this.#subscriptionCallbacks[callbackID];
       // if this is the last subscription, tell the comp manager to stop listening
       specificCompsManager.stopListeningToUnderlyingTelemetry();
diff --git a/src/plugins/comps/components/CompsView.vue b/src/plugins/comps/components/CompsView.vue
index 4a3a52ec6d..46a842287c 100644
--- a/src/plugins/comps/components/CompsView.vue
+++ b/src/plugins/comps/components/CompsView.vue
@@ -26,10 +26,16 @@
       <div class="c-cs__content c-cs__current-output-value">
         <span class="c-cs__current-output-value__label">Current Output</span>
         <span class="c-cs__current-output-value__value" aria-label="Current Output Value">
-          <template v-if="testDataApplied && currentTestOutput">
+          <template
+            v-if="testDataApplied && currentTestOutput !== undefined && currentTestOutput !== null"
+          >
             {{ currentTestOutput }}
           </template>
-          <template v-else-if="currentCompOutput && !testDataApplied">
+          <template
+            v-else-if="
+              !testDataApplied && currentCompOutput !== undefined && currentCompOutput !== null
+            "
+          >
             {{ currentCompOutput }}
           </template>
           <template v-else> --- </template>
@@ -136,7 +142,7 @@
 
 <script setup>
 import { evaluate } from 'mathjs';
-import { inject, onBeforeMount, onBeforeUnmount, ref } from 'vue';
+import { inject, onBeforeMount, onBeforeUnmount, ref, watch } from 'vue';
 
 import ObjectPathString from '../../../ui/components/ObjectPathString.vue';
 import CompsManager from '../CompsManager';
@@ -155,7 +161,7 @@ const outputFormat = ref(null);
 
 let outputTelemetryCollection;
 
-defineProps({
+const props = defineProps({
   isEditing: {
     type: Boolean,
     required: true
@@ -167,11 +173,12 @@ onBeforeMount(async () => {
   outputTelemetryCollection = openmct.telemetry.requestCollection(domainObject);
   outputTelemetryCollection.on('add', telemetryProcessor);
   outputTelemetryCollection.on('clear', clearData);
+  compsManager.on('parameterAdded', reloadParameters);
+  compsManager.on('parameterRemoved', reloadParameters);
   await compsManager.load();
   parameters.value = compsManager.getParameters();
   expression.value = compsManager.getExpression();
   outputFormat.value = compsManager.getOutputFormat();
-  compsManager.on('parametersUpdated', reloadParameters);
   outputTelemetryCollection.load();
   applyTestData();
 });
@@ -179,17 +186,35 @@ onBeforeMount(async () => {
 onBeforeUnmount(() => {
   outputTelemetryCollection.off('add', telemetryProcessor);
   outputTelemetryCollection.off('clear', clearData);
+  compsManager.off('parameterAdded', reloadParameters);
+  compsManager.off('parameterRemoved', reloadParameters);
   outputTelemetryCollection.destroy();
 });
 
-function reloadParameters() {
-  parameters.value = compsManager.getParameters();
-  domainObject.configuration.comps.parameters = parameters.value;
-  compsManager.setDomainObject(domainObject);
+watch(
+  () => props.isEditing,
+  (editMode) => {
+    if (!editMode) {
+      testDataApplied.value = false;
+    }
+  }
+);
+
+function reloadParameters(passedDomainObject) {
+  // Because this is triggered by a composition change, we have
+  // to defer mutation of our domain object, otherwise we might
+  // mutate an outdated version of the domain object.
+  setTimeout(function () {
+    console.debug('🚀 CompsView: parameter added', passedDomainObject);
+    domainObject.configuration.comps.parameters = passedDomainObject.configuration.comps.parameters;
+    parameters.value = domainObject.configuration.comps.parameters;
+    openmct.objects.mutate(domainObject, `configuration.comps.parameters`, parameters.value);
+    compsManager.setDomainObject(domainObject);
+    applyTestData();
+  });
 }
 
 function updateParameters() {
-  console.debug('🚀 CompsView: updateParameters', parameters.value);
   openmct.objects.mutate(domainObject, `configuration.comps.parameters`, parameters.value);
   compsManager.setDomainObject(domainObject);
   applyTestData();
@@ -217,6 +242,9 @@ function getValueFormatter() {
 }
 
 function applyTestData() {
+  if (!expression.value || !parameters.value) {
+    return;
+  }
   const scope = parameters.value.reduce((acc, parameter) => {
     acc[parameter.name] = parameter.testValue;
     return acc;