banners are seen in front of partially transparent blocks like stained glass, water, nether portals, slime and honey blocks as well as name tags from players, mobs and items in item frames. I have a texture pack on in the screen shots but I have tested it without any texture packs and it still happens. It affects windows 10 and mobile and likely other versions.

This only happens with RTX off. I'm not sure if it's related but banners seen with RTX don't show their patterns.