Exploring a world, had this mod since it was generated but a couple other mods have changed along the way, nothing world-gen based though. When exploring a snowy plains, game froze unexpectedly and produced this crash log: https://pastebin.com/qJ5Sg4aL

If it's relevant, I had another feature placement crash from blood magic with the same mods (give or take a few), so maybe its an interaction with another mod? Blood magics was apparently a conflict with scalinghealth (which is still present in this pack), but was fixed in dev for bloodmagic. Here is the blood magic issue: WayofTime/BloodMagic#1795

What other mods are you using? I haven't been able to narrow down a cause for this crash so far, but I think it must be another mod that interferes with how items are saved.

Hey, modlist can be found here, and when you say items being saved a couple come to mind: openloader, crafttweaker (with custom loot and recipe scripts, which work fine functionally in game), and custom starting gear.

Are you able to reproduce this crash?