in the following screenshot, I have a survey ship in a nebula, next to an artifact that is also in the nebula. The artifact is pointed to by the right hand arrow. If I have the ship selected, and RMB on the artifact to send the ship there, a course is instead plotted to a spot two tiles away in a northwest direction, where the left arrow points. I've tried this on several turns, and watched the ship move and left up two tiles when it should be moving one tile right. On a couple of tries I've gotten the green path to get set on the artifact, but when the ship moves it still moves up left.

Note that this is right on the edge of the map, so that might have something to do with the problem.