The #1 bug (in my opinion, also see feature requested below) is activity not uploaded due to “Connectivity issues” or Zwift crashing. This bug - and it’s surrounding artifacts - embodies much of what is unacceptable in Zwift in terms of maintenance and attitude, followed closely by Image Capture functionality being either broken, unreliable, or both.
Also for your convenience, here are the 5 top voted-for feature requests, as they appear in “Feature Request” section, by order of votes (you can find the full list here):
- Allow Saves Without Exit, 1015 votes, created Aug. 2018
- UTF-8 letters in chat - For non English languages. Please, 514 votes, created Dec. 2018
- Personal Best Bot, 496 votes, created Aug. 2018
- Family and Child Plan Request, 483 votes, created Aug. 2018
- World Switching Please, 383 votes, created Oct. 2018
(As far as I recall, Aug. '18 was the date Zwift moved to new forum system)
Of this list, only the last two were - to a minor degree - addressed, the “Family and Child Plan” only came about because of the COVID-19 crisis.