Bugfix: ensure entities are subscribed to switched-to group before we transition it's children to new group - This resolves an issue when moving around fast with an item in hands, and it suddenly gets re-equipped Caused by backup of player subscription queue, which can "desync" player - they'll move to a new group they're not yet subscribed to. Tests: flew around at 100-speed noclip and monitored subscription queue size. despite backup, it no longer re-equipped my gun