This is happening to me as well. It’s basically impossible to hit the wattage target during workouts because a normal human’s legs can’t spin that fast. Wahoo Kickr which is less than a month old, latest firmware, recently did a spin down, etc. If I shift into a higher gear I’ll feel the extra resistance for a moment but soon enough it drops the resistance down again so I’m spinning out.
I’ve tried everything I can imagine to fix this. Just spin at a consistent cadence and let Zwift figure out where to set the resistance (which it never does), increase gearing, pedal like a madman, firmware update, spindowns, reboots, etc. It just seems broken.
I’m on an iPad pro with nothing but a HRM and the Kickr connected, both via bluetooth. Free rides seem ok but actual training plans, which were my primary reason for signing up for Zwift are currently hopelessly broken for me and it’s quite frustrating.