diff --git a/src/api-service/__app__/onefuzzlib/orm.py b/src/api-service/__app__/onefuzzlib/orm.py
index e89203590..436ecab6f 100644
--- a/src/api-service/__app__/onefuzzlib/orm.py
+++ b/src/api-service/__app__/onefuzzlib/orm.py
@@ -37,7 +37,7 @@ from onefuzztypes.enums import (
 )
 from onefuzztypes.models import Error, SecretData
 from onefuzztypes.primitives import Container, PoolName, Region
-from pydantic import BaseModel, Field
+from pydantic import BaseModel
 from typing_extensions import Protocol
 
 from .azure.table import get_client
@@ -219,8 +219,9 @@ class ModelMixin(BaseModel):
         return result
 
 
+# NOTE: if you want to include Timestamp in a model that uses ORMMixin,
+# it must be maintained as part of the model.
 class ORMMixin(ModelMixin):
-    Timestamp: Optional[datetime] = Field(alias="Timestamp")
     etag: Optional[str]
 
     @classmethod
@@ -257,7 +258,7 @@ class ORMMixin(ModelMixin):
         return None
 
     def export_exclude(self) -> Optional[MappingIntStrAny]:
-        return {"etag": ..., "Timestamp": ...}
+        return {"etag": ...}
 
     def telemetry_include(self) -> Optional[MappingIntStrAny]:
         return {}
diff --git a/src/api-service/__app__/onefuzzlib/proxy.py b/src/api-service/__app__/onefuzzlib/proxy.py
index 24b7daa29..5d062454e 100644
--- a/src/api-service/__app__/onefuzzlib/proxy.py
+++ b/src/api-service/__app__/onefuzzlib/proxy.py
@@ -42,6 +42,7 @@ PROXY_LOG_PREFIX = "scaleset-proxy: "
 # This isn't intended to ever be shared to the client, hence not being in
 # onefuzztypes
 class Proxy(ORMMixin):
+    timestamp: Optional[datetime.datetime] = Field(alias="Timestamp")
     region: Region
     state: VmState = Field(default=VmState.init)
     auth: Authentication = Field(default_factory=build_auth)
@@ -179,12 +180,12 @@ class Proxy(ORMMixin):
             )
             return False
 
-        elif not self.heartbeat and self.Timestamp and self.Timestamp < ten_minutes_ago:
+        elif not self.heartbeat and self.timestamp and self.timestamp < ten_minutes_ago:
             logging.error(
                 PROXY_LOG_PREFIX + "no heartbeat in the last 10 minutes: "
                 "%s timestamp: %s compared_to:%s",
                 self.region,
-                self.Timestamp,
+                self.timestamp,
                 ten_minutes_ago,
             )
             return False
diff --git a/src/api-service/__app__/onefuzzlib/task_event.py b/src/api-service/__app__/onefuzzlib/task_event.py
index 463a731fc..e67b85043 100644
--- a/src/api-service/__app__/onefuzzlib/task_event.py
+++ b/src/api-service/__app__/onefuzzlib/task_event.py
@@ -17,12 +17,12 @@ class TaskEvent(BASE_TASK_EVENT, ORMMixin):
     @classmethod
     def get_summary(cls, task_id: UUID) -> List[TaskEventSummary]:
         events = cls.search(query={"task_id": [task_id]})
-        # handle None case of Optional[e.Timestamp], which shouldn't happen
-        events.sort(key=lambda e: e.Timestamp or datetime.datetime.max)
+        # handle None case of Optional[e.timestamp], which shouldn't happen
+        events.sort(key=lambda e: e.timestamp or datetime.datetime.max)
 
         return [
             TaskEventSummary(
-                timestamp=e.Timestamp,
+                timestamp=e.timestamp,
                 event_data=get_event_data(e.event_data),
                 event_type=get_event_type(e.event_data),
             )
diff --git a/src/pytypes/onefuzztypes/models.py b/src/pytypes/onefuzztypes/models.py
index e54206791..f701a6a9a 100644
--- a/src/pytypes/onefuzztypes/models.py
+++ b/src/pytypes/onefuzztypes/models.py
@@ -535,6 +535,7 @@ class JobTaskInfo(BaseModel):
 
 
 class Job(BaseModel):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     job_id: UUID = Field(default_factory=uuid4)
     state: JobState = Field(default=JobState.init)
     config: JobConfig
@@ -557,6 +558,7 @@ class NodeHeartbeatEntry(BaseModel):
 
 
 class Node(BaseModel):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     pool_name: PoolName
     machine_id: UUID
     state: NodeState = Field(default=NodeState.init)
@@ -620,6 +622,7 @@ class AutoScaleConfig(BaseModel):
 
 
 class Pool(BaseModel):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     name: PoolName
     pool_id: UUID = Field(default_factory=uuid4)
     os: OS
@@ -647,6 +650,7 @@ class ScalesetNodeState(BaseModel):
 
 
 class Scaleset(BaseModel):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     pool_name: PoolName
     scaleset_id: UUID = Field(default_factory=uuid4)
     state: ScalesetState = Field(default=ScalesetState.init)
@@ -676,6 +680,7 @@ class NotificationConfig(BaseModel):
 
 
 class Repro(BaseModel):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     vm_id: UUID = Field(default_factory=uuid4)
     task_id: UUID
     config: ReproConfig
@@ -795,6 +800,7 @@ class NodeCommandEnvelope(BaseModel):
 
 
 class TaskEvent(BaseModel):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     task_id: UUID
     machine_id: UUID
     event_data: WorkerEvent
@@ -813,6 +819,7 @@ class NodeAssignment(BaseModel):
 
 
 class Task(BaseModel):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     job_id: UUID
     task_id: UUID = Field(default_factory=uuid4)
     state: TaskState = Field(default=TaskState.init)
diff --git a/src/pytypes/onefuzztypes/webhooks.py b/src/pytypes/onefuzztypes/webhooks.py
index 1ad661bc3..6f18a2ce5 100644
--- a/src/pytypes/onefuzztypes/webhooks.py
+++ b/src/pytypes/onefuzztypes/webhooks.py
@@ -3,6 +3,7 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 
+from datetime import datetime
 from typing import List, Optional
 from uuid import UUID, uuid4
 
@@ -17,6 +18,7 @@ class WebhookMessage(EventMessage):
 
 
 class WebhookMessageLog(WebhookMessage):
+    timestamp: Optional[datetime] = Field(alias="Timestamp")
     state: WebhookMessageState = Field(default=WebhookMessageState.queued)
     try_count: int = Field(default=0)