- **A slow Design engine start-up no longer refuses a change (#4496).** The short-lived Yjs engine used to share one 5 s budget between starting node with the Yjs bundle and applying the change, so a loaded host could answer `503 Design engine is unavailable` before the change even began. Start-up now has its own 15 s budget and the change keeps 5 s. Either timeout still kills the engine and refuses the change with the same 503 (or websocket close `1011`); the server log now names the phase (`startup` or `work`) that ran out. A process whose descendant keeps the output open no longer holds the request past its budget.