Make any large nuke boom and try to fly into fallout zone - instant crash.
I was checking similar issues here, that bug was happening with Vanilla leaves blocks before.
But this crash happend if Biomes O'Plenty installed:
crash-2024-12-10_23.50.17-server.txt

That's not only BOP. And maybe not BOP.
Im sure that's Recurrent Complex (i have same issue with RC) and maybe, potentially, ANY other mod, that add another leaves \ wood or changes world gen and etc.