The Lotta Terracota vertical slabs don't seem to work with the double vertical slab feature. I have disabled the vertical placement feature for regular slabs.

Yes I am open for pull requests! You might find it useful to use my VerticalSlabSupport class as that generalises vertical slabs so you only need to give the names of the classes for reflection

@CJMinecraft01 are you open to pull requests? If so, I am happy to do the work to add support for my two mods Lotta Terracotta/Sweet Concrete.

This has been added in the latest version!