This occurs when a train runs in reverse to couple to another train (e.g. a loose consist) and there is a reverse point in the same section of the coupled train and the coupling train is partly on a switch at the moment of coupling. At the moment of coupling the switch pins are dealigned (because track sections are provisionally unreserved) and aren't realigned again, because they aren't reserved again. Dealigning the switch the reverse point is no more recognized. It will reappear again when the rear of the train will have passed the switch.
Not seeing the reversal point any more misleads the player, that doesn't know whether he must continue reversing or not.
The patch reserves again sections after coupling, which causes a call to the method that re-aligns pins.
Fixed in x.3527.