diff --git a/clientapi/consumers/roomserver.go b/clientapi/consumers/roomserver.go
index 698581520..caa028ba3 100644
--- a/clientapi/consumers/roomserver.go
+++ b/clientapi/consumers/roomserver.go
@@ -84,8 +84,9 @@ func (s *OutputRoomEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
 		return nil
 	}
 
-	events := []gomatrixserverlib.HeaderedEvent{output.NewRoomEvent.Event}
-	events = append(events, output.NewRoomEvent.AddStateEvents...)
-
-	return s.db.UpdateMemberships(context.TODO(), gomatrixserverlib.UnwrapEventHeaders(events), output.NewRoomEvent.RemovesStateEventIDs)
+	return s.db.UpdateMemberships(
+		context.TODO(),
+		gomatrixserverlib.UnwrapEventHeaders(output.NewRoomEvent.AddsState()),
+		output.NewRoomEvent.RemovesStateEventIDs,
+	)
 }
diff --git a/federationsender/consumers/roomserver.go b/federationsender/consumers/roomserver.go
index ff5230161..a15937f9e 100644
--- a/federationsender/consumers/roomserver.go
+++ b/federationsender/consumers/roomserver.go
@@ -131,7 +131,7 @@ func (s *OutputRoomEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
 // processMessage updates the list of currently joined hosts in the room
 // and then sends the event to the hosts that were joined before the event.
 func (s *OutputRoomEventConsumer) processMessage(ore api.OutputNewRoomEvent) error {
-	addsJoinedHosts, err := joinedHostsFromEvents(gomatrixserverlib.UnwrapEventHeaders(ore.AddStateEvents))
+	addsJoinedHosts, err := joinedHostsFromEvents(gomatrixserverlib.UnwrapEventHeaders(ore.AddsState()))
 	if err != nil {
 		return err
 	}
diff --git a/publicroomsapi/consumers/roomserver.go b/publicroomsapi/consumers/roomserver.go
index 8bfa53569..ba187cb11 100644
--- a/publicroomsapi/consumers/roomserver.go
+++ b/publicroomsapi/consumers/roomserver.go
@@ -86,7 +86,7 @@ func (s *OutputRoomEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
 	}
 
 	var addQueryEvents, remQueryEvents []gomatrixserverlib.Event
-	for _, headeredEvent := range output.NewRoomEvent.AddStateEvents {
+	for _, headeredEvent := range output.NewRoomEvent.AddsState() {
 		addQueryEvents = append(addQueryEvents, headeredEvent.Event)
 	}
 	addQueryEvents = append(addQueryEvents, output.NewRoomEvent.Event.Unwrap())
diff --git a/roomserver/api/output.go b/roomserver/api/output.go
index 4157c19b7..2bbd97af8 100644
--- a/roomserver/api/output.go
+++ b/roomserver/api/output.go
@@ -119,6 +119,26 @@ type OutputNewRoomEvent struct {
 	TransactionID *TransactionID `json:"transaction_id"`
 }
 
+// AddsState returns all added state events from this event.
+//
+// This function is needed because `AddStateEvents` will not include a copy of
+// the original event to save space, so you cannot use that slice alone.
+// Instead, use this function which will add the original event if it is present
+// in `AddsStateEventIDs`.
+func (ore *OutputNewRoomEvent) AddsState() []gomatrixserverlib.HeaderedEvent {
+	includeOutputEvent := false
+	for _, id := range ore.AddsStateEventIDs {
+		if id == ore.Event.EventID() {
+			includeOutputEvent = true
+			break
+		}
+	}
+	if !includeOutputEvent {
+		return ore.AddStateEvents
+	}
+	return append(ore.AddStateEvents, ore.Event)
+}
+
 // An OutputNewInviteEvent is written whenever an invite becomes active.
 // Invite events can be received outside of an existing room so have to be
 // tracked separately from the room events themselves.
diff --git a/syncapi/consumers/roomserver.go b/syncapi/consumers/roomserver.go
index d6f8ad73e..135976823 100644
--- a/syncapi/consumers/roomserver.go
+++ b/syncapi/consumers/roomserver.go
@@ -104,8 +104,7 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 		"room_version": ev.RoomVersion,
 	}).Info("received event from roomserver")
 
-	addsStateEvents := []gomatrixserverlib.HeaderedEvent{ev}
-	addsStateEvents = append(addsStateEvents, msg.AddStateEvents...)
+	addsStateEvents := msg.AddsState()
 
 	ev, err := s.updateStateEvent(ev)
 	if err != nil {