Sorry for the frustration. You were not alone in experiencing problems – it was indeed a problem on the server end. Our monitoring tools noticed it as well, and the server team is investigating the cause now. Once we identify the cause and implement a remedy to prevent future recurrences, we will then begin the work of assessing why our testing missed the problem, and amending our testing procedures accordingly. We agree that server problems like this are not acceptable.
Zwift really needs to enhance their software to record offline if this happens. Just because we are not riding with others does not mean our workout cannot continue.