That sounds like a bug then. I just tried it with Tyson and got to path B, at least on the PC version. Unless it's only Dean's route that has that problem...
I can think of a couple things maybe? If you're on mobile, it might be a bug exclusive to that version. If the save file is old, that could cause issues as well.
It's cumbersome, but you could try downloading a previous version and using that to get on B. Then just update when you have the right save state. Outside of that I can't really think of a solution if the current update is bugged for you.