Since updating to the latest version of Zwift on my iPad Air 4 (Zwift version 1.19), every world that has daylight has the road I’m riding on in shadow. You see sunlight on features further away, but the road itself (and the riders you can see) are always in shadow. I’ve clocked up about 8 hours riding like this now, and it is always the same. I can provide screenshots if useful.
Night is fine, and things brighten a bit during the twilight times.