Hi there,

It would seem your mod and OSV aren't compatible with one another as mentioned in this issue to another mod dev with whom I thought the issue was for originally.

Minecraft: 1.16.2
Forge: 33.0.37
OSV: 5.5
OTBYG: 1.0.4

PersonTheCat/OreStoneVariants#87 (comment)

I'm going to close the issue as you guys found out where it came from. Thanks again for that!