Cadence fine in "Just ride" but wrong in "workouts"

I know there have been MANY threads about cadence not working correctly for people but the issue for me only seems to be in Workout mode…

I am using a Wahoo Cadence and Speed Sensor on a dumb Turbo. I connect via an Apple TV 4 and use the Zwift companion on my iPhone 11 The Cadence I see on “Just Ride” matches my Garmin Edge and the Wahoo App but as soon as I start a Workout… Boom. its wrong.

It is constantly showing at around 66% Cadence so if I am spinning at 90, it shows 60. 80 shows 50 etc. etc.

This is really frustrating. I have tried uninstalling/reinstalling, changing batteries etc. can anyone give a fix??

Have you tried without using your Garmin Edge, maybe that is mucking up the signal?