No, it's not just you. Same thing happened to me. It's got so bad I have to turn them off to get anywhere. I'll pleased to see the next release of the game, where we can control who is beetling around the galaxy with us!
[spoiler:pnqqmfpg]The spawn-rate should certainly be adjusted anyway, so that it's a very low probability of them appearing in Sol before, say 2050, with a normal TN start.[/spoiler:pnqqmfpg]
That said, I have outfitted my beam ships with ridiculously huge fire controls that will hopefully enable them to track effectively, and I have a PDC with the latest missile tech due in a month, so maybe this time I will survive.
EDIT: Well, that could have turned out worse, two alien ships appeared, one just flew out of planetary sensor range and disappeared, and the other rammed two freighters before blowing up, hopefully I will be able to recover decent technology from the wreck. All in all a better outcome than my last encounter with these "invaders".