Been trying to make a modpack that has shader support, and I have discovered that, as long as RLFoliage is installed, whenever my shader of choice is on (Complimentary Shaders) it causes glass blocks and glass panes to not render a texture. The affected blocks turn 100% transparent when the mod is installed, even if every feature in the config file is disabled.

Thanks for the advice, I will experiment to see what works best for me.

This is an issue with the original BetterFoliage, from what I remember certain shaders set glass to translucent when Optifine itself doesn't usually do that in the first place, which causes some sort of rendering conflict between BetterFoliage and Optifine.

You can try disabling Anisotropic Filtering, Antialiasing, and VBOs in Optifine settings and see if that helps.
Alternatively, edit the shader pack and remove the line setting glass to translucent, layer.translucent = glass glass_pane.

Or, switch to a different shader pack, personally I recommend Sildur's Shaders as they are generally compatible with most 1.12.2 mods.

@Lenvill-Jarlsen Did you figure out a workaround?