diff --git a/changelog/6472.improvement.md b/changelog/6472.improvement.md
new file mode 100644
index 000000000000..f21ae5eb4c08
--- /dev/null
+++ b/changelog/6472.improvement.md
@@ -0,0 +1 @@
+Do not modify conversation tracker's ``latest_input_channel`` property when using ``POST /trigger_intent`` or ``ReminderScheduled``.
diff --git a/rasa/core/events/__init__.py b/rasa/core/events/__init__.py
index 47d7534c09bc..ba0ab1a308b1 100644
--- a/rasa/core/events/__init__.py
+++ b/rasa/core/events/__init__.py
@@ -402,13 +402,16 @@ def apply_to(self, tracker: "DialogueStateTracker") -> None:
 
     @staticmethod
     def create_external(
-        intent_name: Text, entity_list: Optional[List[Dict[Text, Any]]] = None
+        intent_name: Text,
+        entity_list: Optional[List[Dict[Text, Any]]] = None,
+        input_channel: Optional[Text] = None,
     ) -> "UserUttered":
         return UserUttered(
             text=f"{EXTERNAL_MESSAGE_PREFIX}{intent_name}",
             intent={INTENT_NAME_KEY: intent_name},
             metadata={IS_EXTERNAL: True},
             entities=entity_list or [],
+            input_channel=input_channel,
         )
 
 
diff --git a/rasa/core/processor.py b/rasa/core/processor.py
index dd4c00dd928e..20cce0046d62 100644
--- a/rasa/core/processor.py
+++ b/rasa/core/processor.py
@@ -387,7 +387,14 @@ async def trigger_external_user_uttered(
                 f"Invalid entity specification: {entities}. Assuming no entities."
             )
             entity_list = []
-        tracker.update(UserUttered.create_external(intent_name, entity_list))
+
+        # Set the new event's input channel to the latest input channel, so
+        # that we don't lose this property.
+        input_channel = tracker.get_latest_input_channel()
+
+        tracker.update(
+            UserUttered.create_external(intent_name, entity_list, input_channel)
+        )
         await self._predict_and_execute_next_action(output_channel, tracker)
         # save tracker state to continue conversation from this state
         self._save_tracker(tracker)
diff --git a/tests/core/test_processor.py b/tests/core/test_processor.py
index 69eda13519c8..62545ed43396 100644
--- a/tests/core/test_processor.py
+++ b/tests/core/test_processor.py
@@ -182,6 +182,25 @@ async def test_reminder_scheduled(
     assert t.events[-1] == ActionExecuted("action_listen")
 
 
+async def test_trigger_external_latest_input_channel(
+    default_channel: CollectingOutputChannel, default_processor: MessageProcessor
+):
+    sender_id = uuid.uuid4().hex
+    tracker = default_processor.tracker_store.get_or_create_tracker(sender_id)
+    input_channel = "test_input_channel_external"
+
+    tracker.update(UserUttered("test1"))
+    tracker.update(UserUttered("test2", input_channel=input_channel))
+
+    await default_processor.trigger_external_user_uttered(
+        "test3", None, tracker, default_channel
+    )
+
+    tracker = default_processor.tracker_store.retrieve(sender_id)
+
+    assert tracker.get_latest_input_channel() == input_channel
+
+
 async def test_reminder_aborted(
     default_channel: CollectingOutputChannel, default_processor: MessageProcessor
 ):