I don’t agree with this. The application that placed the metadata in the xmp file is irrelevant (ExifTool in my case). What matters is that the photographer determined that the data is important enough to place in the xmp file. It is bad form for Photo AI to discard it without a warning to the photographer.
Lightroom handles the metadata in the xmp files correctly. It applies my copyright data, adds my user comment, and my keywords are added to my photo in Lightroom. If Adobe is able to handle the sidecar file, surely Topaz Labs can too.