Bug description
When you leave and reconnect, sometimes the identities disappear, if you disconnected with an identity equiped. You can fix the issue by killing an animal, dying, going through a nether portal. This is on a server.

Game does not crash

This should:tm: be fixed in the 2.1.0 alpha Forge version, which I will release tonight (a few hours from this post). I would appreciate it if you gave the new version a try and let me know how it goes! It should have much better syncing when going through portals and disconnecting.