There are no textures on the bottom and top of the glass pane, I thought it was my local problem, but I see this on more than one version of the mod and more than one build, and I conclude that this is a skill issue with the mod.

version 0.4.1 minecraft 1.20.1 forge 47.3.10

Nah dw Sasha it's on me, I forgot to push them
Will fix that soon, just couldn't get the time yet

Most likely it's my failure.. so will look at it closer in upcoming version

In WIP version it has been fixed for both Fabric and Forge, and coming in v0.5