diff --git a/syncapi/streams/stream_pdu.go b/syncapi/streams/stream_pdu.go
index 1003208fd..088c1a7ca 100644
--- a/syncapi/streams/stream_pdu.go
+++ b/syncapi/streams/stream_pdu.go
@@ -497,6 +497,11 @@ func (p *PDUStreamProvider) lazyLoadMembers(
 	}
 	// Add all users the client doesn't know about yet to a list
 	for _, event := range timelineEvents {
+		// If we're doing an initial sync, add all users to the state events, bypassing the cache
+		if !incremental {
+			timelineUsers[event.Sender()] = struct{}{}
+			continue
+		}
 		// Membership is not yet cached, add it to the list
 		if _, ok := p.lazyLoadCache.IsLazyLoadedUserCached(device, roomID, event.Sender()); !ok {
 			timelineUsers[event.Sender()] = struct{}{}