Not sure if this is a crash, but for some reason my game closed out, turning my entire computer screen black for a split second. Using 2.0.2.0-pre3.1 on 1.12.2. Apparently it may be the latest version of Optifine, but I'm not sure. Will try downgrading to a version I used when I didn't have the crash.

Optifine can always cause problems

Alright, seems reverting fixed the issue. I'll just stay at this older version until things smooth out. Though that may never happen.