DASD

Some parameters will show a slider in the viewport. Sometimes these parameters get stuck when you delete the node and they are pretty hard to get rid off. To prevent this, I recommend to turn off viewport handles for parameters. You need to restart Houdini to make it take effect on parameters that are already stuck in the viewport. (I'll also make a bug report, but this might help some people until there's a fix):

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: