Resistance control Elite Real Tour USB no longer working

Hi community,

I use an older Elite Real Tour USB which worked so far as charm on my Mac.Power comes from a P2M crank.

However, since last week during race and also free ride, apparently the resistance is way too low, even after I have set the trainer difficulty to the max.

In opposite, in workout mode I can manually control the trainer resistance as before, which also is displayed properly on screen.

So in race etc. I could also feel SOME resistance changes, but as said less than some weeks ago.

Feedback appreciated:-)