I'm currently hosting a server for a group of friends and we encountered an issue pretty much immediately where we couldn't see the graphic for insulation on armor pieces, and we had to rely on NBT data to tell if it was insulated or not. Attempting to apply insulation to armor using the Sewing Table will cause the client to crash. Similarly, viewing an armor piece that already has built-in insulation in JEI's menu, such as Create's Netherite Diving Helmet, will also crash the client.

Neither of these issues were able to be replicated in singleplayer with all of the same mods enabled; they effect the user exclusively in multiplayer.

Crash Log 1 (After applying Chameleon Molt to an armor piece):
crash-2024-04-08_18.40.07-client.txt

Crash Log 2 (After viewing Netherite Diving Helmet in the JEI menu):
crash-2024-04-08_20.07.09-client.txt

Updating to the latest version will fix this

It does in fact no longer crash, thank you so much! It's worth noting that the insulation UI does still disappear when the armor is equipped, but can be viewed just fine when its not. This isn't an issue that impedes gameplay, though, it's all visual. Just figured I'd let you know!