I noticed that at certain spots on the Island course the video would go haywire. e.g. at the top of the climb my avatar rider would go all over the place - even cross-country. Same thing at the bottom of the descent (around the 300 m sign). Also noticed was other riders avatars were all over the road and even going sideways across the road
This is happening because, somehow, you are riding at an incredibly low frame rate; the lowest I’ve actually seen. When the game is running the slow, it wreaks all sorts of havoc with how data is reported.
You want to think about upgrading (according to our data, you are averaging 1 frame per second).
I’ve only just started with Zwift and have only used it to try it out but I have found a similar thing, although this also could be due to using a laptop/poor graphics (so could be low framerate as well).