I had updated and reversed the update to windows 11 version 22H2 (OS Build 22621.521)
I could not enter a new term in my termbase in 2 projects I continued working on after the update.
Error message "Object reference no set to an instance of an object"
After I imaged back to windows 11 version 21H2 (OS Build 22000.1042) the issue disappeared.
I have frozen the update waiting for a better time.