Perk + Achivement Copying Glitch

[RandomChimp]

Very strange glitch, basically a friend of mine copied all my perks and some of my achivements. He went from being 0 in most perks to the same as me (rank 1 and two in most) instantly. He copied the exact same progress also (for example I had 122k dmg in beserk and he also had exactly the same number after the glitch).

His stats went from something like:

0 > 1
0 > 1
2 > 2
0 > 2
0 > 2
0 > 1

When I had at the time:

1
1
1
2
2
1

So he got the best of both our stats, the one he had higher was unchanged, but the ones I had higher were put to what I have. He also got the achivement progess for "I like to Watch" and "Experimentilottacide" at the same time (he went from ~1k kills to ~4.5k kills instantly).

This glitch happened at the exact time I got the "I like to Watch" achivement. As soon as I got it the two friends I was playing with at the time went something like "Wtf, I just got rank 2 beserk?!" (knowing that they had not even got rank 1 yet). For one of them the stats were reset after he relogged, but for the other he has got them permently.

I'm sure some people would love this to happen to them (my friend was not bothered either way) but I would be very annoyed if this had happened to me, as I like to earn achivements as they were intended.

Here is a link to a topic with someone with the same glitch:

http://www.gamefaqs.com/boards/genme...topic=49510932

Anyway sorry for the epic post and good luck figuring what the hell causes this one lol