[1.13.2] Using a newer version of a mod that adds new game objects causes mismatch on multiplayer worlds

[xerca]

I have had this problem with Items and SoundEvents but I assume it happens with other objects as well. The mismatch I'm talking about is that the server will think the item is an item while the client thinks it is another item, or plays the wrong sound, etc. This does not happen with single player worlds but happens reliably with dedicated servers. This basically makes the old multiplayer world save unplayable, so it is pretty annoying.

 

Steps to reproduce it:

1. Create and join a new multiplayer world with a dedicated server using mod that adds Item X
2. Make a new version of the mod to add Item Y. It may need to be registered before X to cause the problem but I'm not sure.
3. Update the mods on client and server
4. Join the same world and be sad