So I was making my way to repconn, fighting ghouls, and all of a sudden my screen went black and the next thing I know I'm back at the xmb screen. I guess it crashed to desktop but on the ps3? My console didn't freeze I just went right back to the game tab and started the game again...weird.

Yep it happens. Cool trick huh?

How common is it?

Not exactly "common" but by no means unheard of. It has happened to me about 4 times in 2 years.

happened me about 3 times already mostly when im leaving a building

happens to me everytime i enter Camp Forlorne Hope,So now im unable to start let alone complete any questline there

Its happened to me about 3-4 times as well. Id rather have this happen than a hard freeze though, at least I don't have to manually turn off the ps3 and back on.