Synching scene objects that don't move often?

Options
I have a game with environmental objects like rocks that can move around from time to time.

When new players join a currently running room the rocks are seen where they were instantiated and the last update to their position before the player joined the room is not seen. The objects are set up as "unreliable on change" and their correct position is only seen to the new players if the object is moved while they are in the room.

Is this intended behaviour or am I missing something in the settings somewhere?

If it is intended behaviour what can I do to make sure scene objects that move rarely are seen in their real position to new players that join a room?

Does the last OnPhotonSerializeView get cached somehow so that new players that enter a room that is in-progress can get the latest game state?

Thanks.