Unfortunately, it has been an issue since TSW2. DTG Matt said it is an easy fix, but no word on it since. Apparently it is because the passenger lights are not blocked by the cab wall, so the cab is also lit up by it.
Why don't they just have someone fix all these easy fixes and be done!? Quit screwing around! There are so many silly things that need to be fixed before pumping out more bug ridden routes.