Many times, in different worlds, I’ve seen a glitch which makes it look as if someone flies out of a bush and onto the road. I see this most when there are lots of riders on a route - such as the start of TdZ stages.
Or are you saying that people are coming out of the recently-added Serpentine 8 route but you can’t access that on your version of Zwift? If that’s the case then you need to update to the latest version.