diff --git a/roomserver/internal/input/input_latest_events.go b/roomserver/internal/input/input_latest_events.go
index 296f20afa..b88dc1764 100644
--- a/roomserver/internal/input/input_latest_events.go
+++ b/roomserver/internal/input/input_latest_events.go
@@ -285,12 +285,14 @@ func (u *latestEventsUpdater) calculateLatest(
 	// then do nothing - it's not a candidate to be a new extremity if
 	// it has been referenced.
 	if _, ok := existingPrevs[newEvent.EventID()]; ok {
+		u.latest = oldLatest
 		return false, nil
 	}
 
 	// If the "new" event is already a forward extremity then stop, as
 	// nothing changes.
 	if _, ok := existingRefs[newEvent.EventID()]; ok {
+		u.latest = oldLatest
 		return false, nil
 	}