Nico had observed that wrong sensors were put into a model file.
I could confirm Nicos observation: I used two models, a "Spitfire" with a GPSLog2 as sensor and a "Giant Stik" with 3 sensors: GPSLog2, a MUI-30 and a MRPM-opto. Selecting model "Spitfire" on my dc-16 but switching on model "Giant Stik" the message "Unregistered . . .Really use this receiver?" " appeared. I refused this and switched the model Giant Stik and the dc-16 off. Switching dc-16 and model Spitfire on showed that both GPSLog2 and the MRPM-opto were incorporated into the model file. So all of sudden you have sensors in your model file that should not be there, cannot be activated and are very confusing.
In my opinion this should not happen and hopefully can be corrected by Jeti.
I attach the .jsn file with the double GPSLog2 sensors ans MRPM-OPTO incorporated