There's also the tank/bomber groups partway from their guard posts to your ships that keep juggling back and forth. That's them wanting to go after your stuff but being "leashed" back towards the guard post because they aren't allowed to get much further away than that.
I've noticed that a few times recently, too, and it definitely at least looks buggy, because pretty much every time I've seen that kind of dancing movement without making up their minds one way or another in any other game, it's always been because of some kind of bug.
Even if it's a result of them doing what they're supposed to do, it still looks kind of ridiculous to have them diligently patrolling a tiny patch of space in the middle of nowhere instead of obviously guarding something or attacking you. If they were a bit less spastic about it, they'd at least seem like they're swarming menacingly and trying to cut off your route to something important, but they come across more like they have extreme ADD with a 1.5 second attention span or something. Heh.
Not exactly a major issue if it's mostly cosmetic, though.