Filament Hub False error on retracting filament

I cannot get the A1 mini to reload filament. In the middle of a multi colored print on my A1 - mini with AMS Light the filament retracted for the change and then error messaged that the filament did not retract and a filament clog occurred or the filament has broken.
I could not see any filament broken. So I did the procedural disassembly of the extruder and there was nothing in the housing. The extruder was and is empty and clear. So when I restarted the AI and tried to load a new filament, it tries to retract a filament that is not there and spins forever. When it stops it claims there is a clogged extruder.
It never tries to feed the new filament because it thinks there is still a filament in the extruder and there isn’t. All 4 filaments are clearly retracted about half way back to the AMS Light spools. there is no filament protruding on either side of the filament hub and no way to check to see if there is a small piece in it.

Look inside the filament hub, I’ve had this happen once before.

Thanks for the reference. Found it and remedied the problem.