The texture format capability tables say that copying into depth32float is not allowed at all. However, the Copying Depth/Stencil Textures section says that you can copy depth32float -> depth32float or depth32float-stencil8[depth] <-> depth32float.

I can't remember offhand if there was another reason we needed to disallow this depth32float -> depth32float, or if it was an accident that we ended up disallowing these copies. Also not sure about depth32float-stencil8[depth] <-> depth32float copies, I have a stronger recollection that some devices couldn't do that.

Need to go digging to find out whether the prose is wrong or the table is wrong.