Maybe it's just the way the NPCs' flight style is.
I remember from Vanilla that different factions tend to fly in different methods.
Xenos then to "snake" their ships up and down.
Bunters will strafe.
Corsairs in Titans will have the person being shot at be the bait while the others go behind you and pound you from behind.
Maybe it's just a thing that the GRN NPCs do. Not sure if any other faction out there have similar flight patterns, though I know new faction flight patterns are copied from Vanilla ones. Eg: I think Council ships fly in similar ways to the Corsair Titans.