Filament sensor does not stop the print  

Filament sensor does not stop the print

I experienced a first filament runout on my Mini (with the optional filament sensor) and was surprised that the sensor did *not* stop the print (from USB stick).

I checked my wiring, no problems there. As I had a spare sensor on hand (just ordered one a week ago for my other Mini) I replaced it, but was surprised to find out that the Mini *did not stop the same print from USB stick* again with that freshly unpacked sensor!

What could be wrong here? Some fault on the board? I double checked the connection, again, no problems there, both sensor cables click in like they should.

As this was my first filament runout I am not even sure, how the filament sensor should behave. Same as on MK3S, where menus change immediately and asks for temperature? On my Mini the display never registered insertion of new filament, is this normal behaviour?

Thanks for help in advance.