TSS and elevation in FIT file not matching source data

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?


Oh and before someone mentions it, my garmin 520 has the correct inputs, such as crank length and my weight matches my weight on zwift, which if different could have caused a difference in TSS.

what are you using to view the fit file? strava shows end minus start altitude instead of total up and down.

also TSS is dependent on your FTP, not your crank length, or your weight… is your FTP set to the same on both programs?

Alex, You are correct. My Garmin edge 520 had reset all my settings on a recent update and lost all my previous setup, including my FTP which was 210W on the garmin and 240W on zwift, hence the difference in TSS. Thanks