I don't know what else to say about this. All I am seeing is a lot of stuff about sodium, the mixin mentioned in the title of this issue, and something about making something transparent. I have attached the crash report to see if you can make anything of it.

latest.log

Ok, you're gonna laugh at this. I removed the mod "seamless loading screen" and it loads just fine now. I should've tried that sooner. Issue closed!