When placing glass item frames the texture appears broken (the pink and black box). Once you place an item on the glass frame it seems to be fine. Same goes for the Dyed item frames, however they do not fix once an item is placed, but stay broken and you cannot see the item or frame at all. Picture attached, regular item frame included for comparison.
Version 1.16.1, Forge 32.0.108, Quark 2.2-258

Can you reproduce without optifine/shaders?

Okay, yes, it seems to be fine when I remove Optifine. Shaders on or off do not make a difference, only removing Optifine does. :(