3rd party AU plugins no longer showing in Logic tracks
I have a few recently acquired 3rd party AU plugins (they are from 3 different vendors) that have been successfully validated and correctly showing in Logic plugin manager; they showed normally for a few days on the tracks after installation, and I was able to use them as expected; then, they suddenly disappear from the tracks AU list, though still showing as successfully validated in plugin manager and they have been reseted and rescanned; I suspect it's a Logic issue as they've been working normally with another DAW I use; iMac Retina 5k, 27 inch, late 2015, 4 GHz Quad Core Intel Core i7, 32 GB RAM, running Monterey 12.6.5
Thanks for any help
iMac 27″, macOS 12.6