DASD

It's probably best to report it as a bug.

If I'm not mistaken, your issue occurs because Houdini does not recognize all of your UV attributes as UV attributes.
When you create UVs with standard Houdini nodes made for the purpose, they get a hidden flag that they are indeed UVs.
But if you create an attribute with a name that seems like the name of a UV set, or copy and rename one, it might not do that. If you middle-click on the node you might see something like:



You can set an intrinsic attribute to tell Houdini that you are indeed creating UVs:


This code probably works in different wrangle modes (Detail, Vertex, ...), but you need to only set it once, so it's best to run in Detail mode:

This might not be relevant, but when I had texture cache update issues with baked textures (that did not show on materials), this did the trick for me:

hou.hscript("glcache -c")

You can also try:
hou.hscript("texcache -c")
or
hou.hscript("texcache -n")

(This is also kind of a note for myself for future reference.)