This results in the mule dragging the player around until they cancel docking. I assume the sudden acceleration of the player's automatic docking maneuver makes them think they need to match speed. There are two possible improvements here:
1) If a ship's order giver is trying to dock with it, it should stop rather than continue trying to follow.
2) Reduce the strictness of docking requirements to being within a small distance of a docking port and having relative velocity below a reasonable value. This would make it possible to dock with moving ships/wrecks, instead of being dragged until they stop.