How should the import handle Free Ride efforts imported from Zwift, just indicates an error and 0 watts. Suggestion would be to import them as slope mode at some configurable %. Default 1% @ 50% of TP.
Most of the workout should import okay - you may need to manually adjust the free ride intervals in the Workout designer. You’ll want to change those free-ride intervals to SLOPE and select the interval target.
See if you can PM me the original Zwift file you’re trying to upload, as well as the workout import settings. We can take a look and see if that’s something we could improve in the future. Cheers!