I'm on my 34 Sith Marauder in Taris. Was getting extremely frustrated with this exact problem. On my fourth run trying to get through a story phase, I noticed that it wasn't Jaesa jumping in the middle of unsuspecting mobs. The NPCs were attacking us from an obscene distance and that was just her response to the threat. So, in dismay I couldn't take her back to the ship for a good spanking... well, I still could and may yet, but that's beside the point. Anyway, it appears it's a mob aggro radius issue and not a companion random evil streak. Just my 2 credits worth.