Suddenly in OS Monterey, trackpad plus highlight the text to copy stopped working. It would think I was asking for a dictionary definition or something. Don found an article for how to stop pboard running, either in Terminal with killall pboard or in Activity Monitor and force quitting pboard.
The article that covers it is here on SetApp.
And then it occurred to me that the dictionary look-up that kept popping up might be interfering with copy/paste.
I found an article that showed how to stop it popping up. It’s just a matter of going to Apple Preferences, trackpad, Point and Click, and unchecking Look up and Data Detectors.