Kickr Power/Speed Readings

Dear Zwift, Today Zwift revealed new anomalies I had not noticed before. As I was trying to discipline myself to have easy spin days I stayed in my small ring the whole day. Using a much smaller gear than normal the power and speed readings where not proportionally down. More noteworthy was the downhill section where regardless of my cadence or power my speed would spike up to about 45-46 mph but no matter how hard I have pushed in the past it never seems to go past 47 mph. In fact today I intentionally tried to back off almost completely and I still reached 45 mph. I have done the calibration with the spin down.

The power reading on Zwift is way below the watt indicator on my Kickr trainer app… Any explains toon for this ?