RP custom variations in the terrain_texture.json does not work properly.

When adding texture variations with a resource pack via terrain_texture.json only the first or last texture loads. Each time I load Minecraft more blocks have this problem.

To replicate this download a resource that adds texture variations to blocks, specifically logs, and load it in a new world. Place down blocks the are coded to have texture variations. The block will load only one of the texture variations.