Minecraft v1.16.5
Forge v36.2.4
Double Slabs v3.7.1
Better Nether Reforged vbeta2

Slabs from Better Nether Reforged render incorrectly as vertical slabs.

Hi there! Apologies for the delayed response, I've had a hectic year at university and have only just got round to checking the issues with the mod. I have now fixed this I believe and will add the fix in the next version

No problem! College can be busy for sure