src/app/editor/[projectId]/FlowchartEditor.tsx

@@ -566,6 +566,11 @@ function FlowchartEditorInner({ projectId, projectName, userId, userDisplayName,
       },
       onPersist: async (persistNodes: FlowchartNode[], persistEdges: FlowchartEdge[]) => {
         try {
+          // Auto-persist saves the current state for durability. We do NOT
+          // broadcast state-refresh here because CRDT already syncs nodes/edges
+          // via yjs-update broadcasts. Broadcasting here causes ping-pong:
+          // other clients fetch from DB, overwrite their local variables/characters,
+          // then their persist writes stale data back, causing a loop.
           await supabase
             .from('projects')
             .update({
@@ -577,8 +582,6 @@ function FlowchartEditorInner({ projectId, projectName, userId, userDisplayName,
               },
             })
             .eq('id', projectId)
-          // Notify other clients to refresh after successful auto-persist
-          realtimeRef.current?.broadcastStateRefresh()
         } catch {
           // Persistence failure is non-critical; will retry on next change
         }