I've found a bug where the tab key is improperly functioning with both forge and liteloader on this mod. Tabbing doesnt actually autofill the chat segment you are at, and instead tryes to autofill from every available command on the server, which when on a server with 111 Plugins (Yes, i know its a bit crazy), almost immediatley crashes the client.
Sometimes it doesnt do anything at all, but after a while it'll cause this. The only way to play afterwards is to delete the logs for that specific server, and try again.
Thought this'd be worth mentioning.