About Picture Perfect Achievement

[Red Hot Chili Peppers]

Hey guys! I've collected all 42 victims photos but ach. didn't pop. When I looked the backpack I can see all 42 pics but If I look the ach. progress I see 41/42 photos collected. What do you think? I couldn't solve it...

[thebaconson]

How's your internet connection?
I have played other games where dropping offline has caused these issues. It isn't one I have experienced myself with this game as I have that achievement.