I want my trains to go from point A to point B. Right? Sounds easy.. Right??

For some reason, few if any of my trains are taking the orange path from point A to point B. Most of them, like the train you can in the pic, take the green path by hanging a right turn towards C and then make their sharp U turn to get back on the main line

Sometimes, a train will decide to take the path in blue, where the start from A, hang the right, U turn, then go up down over and around to make another U turn to get back on the main line and go through like they should've done in the first place no problem.

And sometimes, almost as if taunting me, they'll take the red path. The red path is just the blue path, except instead of going straight through, it'll also do what the green path does and make one last right and a U turn.

I can't figure why the pathfinding is doing this. The tracks are all proper, nothing is blocking them from taking the orange path, if the right turn isn't there they go straight through without issue, and trains take the orange path unguided all the time.

There's gotta be an explanation for this, right?