props undefined at boot in reviver.ts

Uncaught TypeError: Cannot read properties of undefined (reading 'props')
    at boot (reviver.ts:287:33)
    at waiting_room?from_login=true:5987:44916

 else if (comment === "/frsh:island" || comment === "/frsh:partial") {
      node = maybeHideMarker(node);
      const item = ctx.stack.pop(); // the offending line
      if (item !== undefined) {
        item.end = node as Comment;
      }
    }