Since there are no error codes a software bug is the most likely culprit. Try resetting your MMI system by holding down the volume button. If that doesn't fix it you'll probably need to take it to the Audi dealer. They might need to update the software. These digital displays can have some odd...
I agree with @hot_papieeto3 relax, it doesn't! You're just turning off one specific feature. Still getting that sweet regenerative braking and all the other energy-saving goodness.