I think its a compatibility problem because of all the mods i have.
Here is the log
latest.log

I'm confused as to where I should put this ... here or #499 ... so I guess I'll just comment in both places? I apologize for any inconvenience this might cause. Thank you for your time & help. =)

Renaming VanillaFix.jar to _VanillaFix fixes the crash for me ... however ... BetterPortals gives me constant spikes. It doubles garbage collection and cuts my FPS in half. =(

MC: 1.12.2
Forge: 2847
Optifine: F5
BP: 0.3.7.7
Forgelin: 1.8.4
Quark: 179 / AutoReg: 32
VanillaFix: 1.0.10-150
JEI: 291
No Resource Packs or Shaders

Probably with MixinBoostrap.
Try renaming it to "aMixinBootstrap-1.0.2.jar" so it's loaded before BP.
If that fixes it, then it's the same underlying problem as in #499 which will probably be fixed the next time I release a new BP version.