Just yesterday it was all ok (speed fluctuating in zwift as you ran faster/slower), but today in zwift runs the speed is fixed to the speed the manual treadmill was reporting at time of pair.
I did around a half dozen tries and each was a different speed but the zwift avatar keep moving at the pace of pairing even if I stopped. It was funny to see cadence at 0 but a run speed shown. And it was also funny to see a running cadence and the avatar walking.