diff --git a/src/models/event-timeline.ts b/src/models/event-timeline.ts
index 67be25fbc9c..a20dac880e4 100644
--- a/src/models/event-timeline.ts
+++ b/src/models/event-timeline.ts
@@ -458,7 +458,7 @@ export class EventTimeline {
                 // member event, whereas we want to set the .sender value for the ACTUAL
                 // member event itself.
                 if (!event.sender || event.getType() === EventType.RoomMember) {
-                    EventTimeline.setEventMetadata(event, roomState!, false);
+                    EventTimeline.setEventMetadata(event, roomState, false);
                 }
             }
         }
diff --git a/src/models/thread.ts b/src/models/thread.ts
index f2420842dfc..05e847594af 100644
--- a/src/models/thread.ts
+++ b/src/models/thread.ts
@@ -254,6 +254,7 @@ export class Thread extends ReadReceipt<EmittedEvents, EventHandlerMap> {
         if (!eventId) {
             return;
         }
+        // If the event is already in this thread, bail out
         if (this.findEventById(eventId)) {
             return;
         }