3D inventory models transformed into 2D inventory models have a non-transparent background

When 19w42a came out I joined a server and realized my textures I use were glitched in the new snapshot. It islike the bug with the transparency on some items, but this time it only happens when 3d inventory models are made into 2d ones, as an item form. Here is a comparison of 19w40a and the new snapshot. (These 3d models for blocks have been changed to 2d ones and glitched out in 19w42a with the new rendering engine)