I first encountered this problem with the latest version 2 weeks ago and now I am having the same problem with reinstalled Topaz Photo AI 1.34. In the past when I selected an image in Capture One (16.0.1.17) and chose “Edit with”>“process with Topaz Photo AI” the resulting tif file would show up in the Capture One catalog. Now the tifs are being saved to the hard drive but not appearing in the catalog. I have to manually import the file from the hard drive. I have not changed the Capture version during this period.
It looks like the plugin is calling an older version of Photo AI.
Please uninstall all versions of Photo AI from your computer. Then, grab a new fresh installer for the latest version of Photo AI. You can download a new installer from the downloads page directly. https://topazlabs.com/downloads/
Run that and see if the plugins are working properly after.