version 1.12.2

forge 14.23.5.2860

ruins (Jun 7, 2019)

crash report

latest log

-how to reproduce

1. maybe I see an ore top structure in ruins mod (big ore top)
2. then I leave and enter again the world
3. this crash happens

big ore top doesn't make this crash. I misunderstood XD

It appears to be crashing because it tries to load some entity from NBT and fails. Ruins does not modify entities. I would suspect something else from your long list of mods

That being said, i do not support 1.12.2 anymore

ok bye...