In an heroic effort to push Zwift to sort on the issue … here my answer to a submitted support ticket.
The ticket …
Thanks for contacting Zwift!
Looking through your logs, I see that this issue was caused by multiple interruptions in your internet connection. You’ll want to do what you can to improve your connection to your network in order to prevent this in future rides.
Sorry there’s not more we can do to recover your lost data.
My answer …
Thanks for your answer but I strongly disagree when you say there is no more to do.
Internet is internet and is so obvious that interruption may happen, and Zwift is a net product. I lost rides in the past and looks like will happen again in future. Other users will no doubt.
So said, what I’ll do (and @65 years old I’m blessed with more than 40 year’s experience on the field) is
Place a Check missing rides button in the game.
At workout start, obtain from your server something like a signing cookie, we don’t want users to submit crafted fit files.
At workout end, digitally sign the fit file.
At workout end, upload that file or do what else you do usually.
If the upload fail, let the user ask to redo via the new added option.
As simple as that. No more tickets to answer about missing rides, no wasted time looking at logs and telling users how to improve their connection …