https://pastebin.com/Sw8px1hg

My client suddenly crashed whilst viewing the guide book. I have an idle timeout on my server, and it's very possible the 7 mins were up, but I'm not 100% certain. Meaning its possible the crash is related to being kicked from a server with the book open. I was viewing the coffee chapter if that's of any use.

Just did another two tests: First I left the table of contents open in the guide book; same crash, after exactly 7 minutes(i.e. my idle timeout period). Second, I opened the book and kicked myself from via the server console: same crash.

This leads me to believe the NPE is related to being kicked in general, not just via idle timeout.

I forgot to mention this is with AA r134, on mc 1.12.2, with forge versions 14.23.3.2669 (server) and 14.23.3.2668 (client).

Weird. Only way that crash happens is if the gui tries to close when the client player is null

Just a hunch, but maybe some functionality is being executed at the wrong time? I should note that I don't crash immediately on kick; I get the dirt screen for a few seconds, but instead getting the "you've been kicked" text, I get a CTD. For example, maybe your gui cleanup is being executed later than it should be?