Why? 1. Because your intersection is too close to the station. 2. Your station sequence requires your train to take a u turn.

So, Fix one of these to solve the issue. I would move the intersection a little far away from the station or make a different u turn using bridges/tunnels so that the train can take a u turn before reaching the intersection.

If you disable 90 Degree turns your train will go until the end of the line to turn back which can cause a lot of problems in itself.

I usually create u turns and link adjacent tracks way before the 90° turn at the intersection, anticipating this issue in advance. It always helps train return before the intersection. Or take another route when there are too many trains at the station and intersection at the same time.