Just now I have updated four mods including Thermal Foundation, Thermal Expansion, Tinker's Construct, and, of course, LevelUp2 to their latest release. But what is funny is that when launching the game, Deep Mob Learning gave a failure when constructing. Firstly I tried to revert TiC, TF and TE but DML still failed to be constructed and the crash report looks all the same. Despairly I tried to revert LevelUp2 to 1.2.6 and the game successfully launched. I'll put the crash reports below and it's a bit abnormal that it generates two reports at a time.

https://paste.dimdev.org/radazikoza.rb
https://paste.dimdev.org/reporomaru.rb

Thank you very much.

That's a bit of an odd crash, since the deobfuscated name for the one not being found is EnumFacing. I'm not 100% sure how that's happening.

Just on a whim, does it happen with FastFurnace uninstalled? It might be that compatibility mixin.

Removed FastFurnace and tried to launch it. Crash still happened and the report looks the same.

I'm unable to reproduce on a fresh instance. You might need to reinstall Forge.

Alright, I'll try later.

Just successfully lauched the game with the brand new 1.4.0. Thanks a lot.