Had this happen 3 times now, and seen a few other people reporting the same issue on reddit. So far it has happened to me only whilst changing seats (in order to jump out the other side), however the other reports I have seen people are just driving. So far I have been unable to reproduce it on demand, but every time it has happened I have double checked afterwards that the windows were closed and remain unbroken. So far i haven't been able to reproduce it with no mods, but since I also can't reproduce it on demand even on the save it keeps happening on this isn't definitive. Other people reporting the bug are not using any vehicle or other likely culprit mods.
Current left field 'theory'; only 'fake dead' zombies are able to attack through the windows. I have no evidence for this, but it would explain why it is relatively rare and I can't reproduce it on demand.
