Shield texture no longer supports transparency

Before the 19w45a/b snapshot, with a resource pack, you could make the shield transparent, but if you styled it with a banner pattern it wouldn't work. (Yes, I made the shield_base, shield_base_nopattern, and all of the patterns in /textures/entity/shield/* transparent) However, after this change, "Shield patterns are now using alpha channel instead of brightness" (https://www.minecraft.net/en-us/article/minecraft-snapshot-19w45a) even the normal shield won't be able to go transparent. I've attached a resource pack below, which says 1.15.X because that's the version that I thought the transparent patterned shield work in. With this, there are a few other things but mainly in 1.14 shields without patterns are transparent. In post-19w45a nothing is transparent.

I believe this texture change doesn't read the png transparency - it uses pre-defined transparency that are defined in the code and overrides the png file, which is very annoying.