If doing a workout and you increase or decrease the difficulty the target watt is wrong. For example if the target watt is 125 Watts and you click the increase button up to 10% the app will show 135 Watts instead of 150 Watts. In The Companion app the right Watt number are shown.
There are a few different reasons why this issue could be happening, but I suggest double-checking to make sure you have the most current version of the Zwift app and Zwift Companion app on your devices.
For additional assistance, I highly recommend that you please submit a support ticket if you haven’t already done so, and one of our support agents will be happy to take a closer look at this matter.
Include the screenshots from this forum post in your support request, and please provide the name or names of the specific workouts where you encountered this problem. If they are custom workouts and you have access to a computer where the workouts were created, please send our team a copy of the .zwo file(s), which can be found the Documents–>Zwift–>Workouts–>(your Zwift ID) folder.