Sadly it looks like developers really fixed the visual issue (carriages not following locomotive) instead of actual bug (locomotive not following its planned path). Having the whole trains going the wrong way does not make them any more functional.
I would vote for another temporary fix - just like carriages now snap to follow the locomotive, the locomotive could also snap to its planned path, not following the global setting of the switch. Sure it will be irrelevant when definitive train system is released but it would make trains useful in the meantime.