Don't put tractor beams right next to the minefields. This isn't actually something we even consider a bug, per se, and I'm not sure it will ever be "fixed." When you have tractors right next to a minefield that's around a wormhole, the tractors will pull ships out of the wormhole and they wind up being too far away from the minefield. If you want the enemy ships to fly through your minefield, don't combine that minefield with tractors. Or have the minefields more spread out, but then it's just pot luck.
Well that's useful to know. I usually use both on anything I want to defend. I guess I'll just stop ever building minefields then. Doing some smattering of damage to incoming ships is not going to ever be as useful as being able to keep them from making a beeline towards my command station. Maybe if this is a thing you'll never fix you could put some kind of in game reason for it (incompatible fields interacting, some kind of sci-fi technobabble reason) and actually make it impossible to place tractors and mines within X distance of each other, so that new players don't do the obvious thing and put these things on the same wormhole.
