I think I know what you're talking about. It's the weird road or path glitches that rip through a map sometimes.I know they are sometimes caused by certain really old road layouts or interchanges from around the time the game came out. Messing around with road anarchy mods and/or Move It can also cause it, but in my experience that's less likely to happen.Have you been building your city up in the same way each time? Perhaps there is a space on the map that triggers it or some interchange you're using each time since it keeps happening for you.I haven't encountered a map having it happen consistently, but I guess it's also possible. What map are you using?