I’ve had a similar problem – I think the problem lies in the code that loads the Firefly database on a file scan that’s the problem. I was able to work around it by directly modifying/fixing the database, that’s not so scary as the schema is quite simple.
You need Firefox with the SQLite Manager add-on to modify the Firefly database file.
If you want to come back to me on it & what your confidence level might be around that task I may be able help with some instructions.