I have made a rather complex model for minecraft block in blockbencher, and like fig.1, it looks very fine in blockbench. The texture and uv bindings is like fig.2.
But when I view this model in minecraft 1.21.1, all the texture's uv get broken. I include the blockstate file for waxed_weathered_cut_copper_stairs and give this model to some of the states there. From fig.3 we can tell that the model is fine, and all the textures is loaded, but the uv mapping seems broken.
I got some message related to this in the client's log:
[21:19:04] [Render thread/INFO]: Exception when loading minecraft:waxed_weathered_cut_copper_stairs texture, using material colour.
[21:19:04] [Render thread/INFO]: No texture minecraft:textures/missingno.png