I have found that whilst I can download a .fit file from Zwift and upload/import it without problem to both Strava and Golden Cheetah, the same file appears corrupted if uploaded directly to Cycling Analytics (cyclinganalytics.com).
Here’s a screenshot: https://www.dropbox.com/s/mg5bibsytmsjvh1/zwift_cyclinganalytics.jpg?dl=0
Heart rate and elevation data disappears, and all other data is corrupt.
I can export the same file from Golden Cheetah to Cycling Analytics and it appears fine, so there is something in the fit file, as it is written by Zwift, which is upsetting Cycling Analytics.
This is occurring consistently.