I trust you because other people have said to have found sectors like that.... though it seems to be very uncommon. It shouldn't happen and there are numerous protections against it happening. If it happens again to you (or anybody) what would really help is a save file. Just save & quit and send me (zasdarq@ftlgame.com) the "continue.sav" from your FTL user folder. Check the announcement post at the top of this forum to see where that is for your system.
Matthew Davis, Subset Games Developer - If you're looking for tech support, you'll get help faster emailing directly, contact info here