As I said before, please read the OP's original post!
If you did so, you'd have seen that he said "If your alarm goes off the same time you receive a email (gmail app) then it turns your alarm off". to which I replied that it was the arrival of the email (or in your case, a message!) that turned the alarm off. The likelihood of the two events occurring at exactly the same time was purely coincidental and most unlikely to happen.
So since it's unlikely (it's not) it's not a bug?
Doesn't have to be the same millisecond you get an email the alarm just has to be going off. It could be 20 minutes after the alarm start (granted you probably won't wake up then anyway) but if you hit snooze it could be an issue.
I've often wondered why my alarm wasn't going off when I wake before it, hop in the shower and after the alarm time it's not going off. It's because I got a notification in that time. Granted again this hasn't been an issue just an odd inconsistency.
Regardless of the situation and how likely or unlikely it is to happen it's still a bug that should not be overlooked. That's just substandard and for you that level of quality may be ok, but for me (especially since I use my iPhone as an alarm) I feel it should be fixed.