After several rides now I have noticed a difference between what I am seeing in live data and the exported .fit file from Zwift.
With my last ride, a figure 8 Watopia ride. The 2 main data differences I am seeing is in Elevation, Zwift data on the top of the scrren may be showing 265m climbed, later the fit file shows it as 210m. Also, my power is being pulled from my Vectors, the power numbers on the zwift screen and my garmin 520 are matching (same power source) but my Garmin is showing a Training Stress score of 75 when the fit file output for TSS was 55.
What is happening to the Fit files, the data is not reliable and is affecting stats, can you look into this Zwift?