I've noticed when using the shootout rails the ships flies mostly up from the pickup rail instead of forward, because of this I'm not able to shoot a ship towards a warp gate or something because it cause up instead of only forward.
It also seems to happen sometimes when undocking from a rail block using logic.
See GIF for more on what happens.
I was trying to build a system to transfer docked entities from ship to ship, for example cargo transfer.