Minecraft version: 1.20.1
Mod Loader: Fabric 0.17.2
Mod version: 2.3.1
Additional mods/log: https://mclo.gs/Ptt9wDe (I also tested with just Additional Placements and got the same issue)

Vertical slabs do not have their UVs rotated on the slim side (i.e., not facing up or down, not the flat face). This causes issues with basically every vertical slab, but is most visible with variants of stone tiles, where the seam is very obviously not in the correct spot.

It seems like the UVs might be extremely inconsistent, however, and change from load to load.