Yes on the display it is a green dot at all times and on the print head itself it has a white led on.
Can you advise more details on inspecting the sensor? I am not sure what parts need to be taken off (if any) in order to access the sensor and evaluate.
Here is an example of what the printer sees. There is no filament loaded. The left nozzle it believes has purple filament in it. I cannot use the connected AMS as the printer still believes the left nozzle has filament loaded.