I've actually seen this happen in all the tiers at one time or another. Seems to be a spawn point nearby. We cleared the area out of klingons and went on our merry way. I few battles later I went boom and when I respawned there were 3 birds of prey and 2 warships sitting there. The first time I went boom, the second time I tried to lead them away before going boom. The third time I went boom a whole bunch of colorful metaphors could be heard wafting through my house. The 4th time I wanted to find a dev and shove my keyboard somewhere uncomfortable. I couldn't even warp out. Luckily the servers went down shortly thereafter.
Are you kidding? Missions going from Klingons to Romulans was like battling Orcs for the first 10 levels and then smacking an Elf, watching it go down, and then being surprised when it doesn't get back up. Romulans are stupid easy compared to Klingons. Their ships blow up faster and on the ground, they're content to stand way over there and let me shoot at them instead of ripping my face off like Klingons did. I can't WAIT to get back into Romulan space.