What the title says. Leaving the Gizzard Stone behind when you exit a room cause Ro Bin to teleport outside the room's bounds. Leaving the room again with the stone will teleport him to you.
Steps to Reproduce
1. Bring Ro Bin to any interior. 2. Leave the gizzard stone in the interior and exit. 3. Open minimap. Ro Bin's icon appears outside any interiors. 4. Go back into the room. The Gizzard stone is there, but Ro Bin is invisible and you can hear him hoping against the wall trying to reach the stone.
This issue has been fixed in either a future version or updated in a previous version.