There was an issue reported last July where certain avatars were not visible in races sometimes, but it seems to have become more pervasive in the last way release. I have won my last two races; however, apparently no racers could see me in either race.
In July this seemed to be isolated to or at least primarily Apple TV users. However, this version of the issue presents across multiple platforms.
In both recent races the position / placing indicator was broken the whole race, ie in one race I was shown as 37/42 the whole race and the other 72/75 the whole race.
My understanding from the past is there is a known issue where zwift places racers in “separate identical” races. Initially this seems to fit that known issue; however it is happening with increased frequency and scale.
I would like to emphasize this is 100% not a network or local issue. This appears to be an application issue or a web service issue.