I have been a longtime Tacx user and recently have been trying Zwift and I love it. Paired ok but the data reading in Zwift is not in synch with what is uploaded to Strava. It also seems, just from feel of resistance/cadence, like I should be registered as going a lot faster and cadence higher but zwift seems to undervalue the data coming from the Bushido for some reason. Strava upload is higher and more in line with what I feel.
Moving to troubleshooting forum.
Are you comparing the output from two different programs to get different numbers? Strava should be reading directly from Zwift’s fit file, so there shouldn’t be any difference between them.