Bug in action
some slabs only return one copy when broken from vertical orientation, or when broken reset themselves to horizontal alignment.

P.S. Realized I still had klee-slabs installed, will try without.

Since no further response has been given I will assume this has been fixed.

ADHD is so real sorry, Yes, without Klee-slabs installed slab breaking works as intended, I do not know if this issue would be fixed through their mod or yours.

It shouldn't be having any issues with block drops now as the vertical slabs now retain all of the original slab properties. As for returning to horizontal placement, that may or may not be fixed - what happened in older versions was placing two vertical slabs together created the original doubleslab variant, without any distinction for the original vertical state.