Forum:Strange glitch with class mods

I've recently started farming Crawmerax solo but I've discovered a couple of incredibly nice class mods doing this but then when I save exit and join a new game a couple of my mods I found have disappeared. I found one called the Professional Dahl Enhancement Mod which did 50% all weapon damage +3 Quicksilver +3 High Velocity then the other one which disappeared on me yesterday was Mercenary with 61% SMG damage +3 Quicksilver +4 High Velocity +3 Girl Power +21 SMG Ammo Regeneration (nearly shit myself when that dropped cuz it's basically the best stats I've ever seen)

Just curious if anyone else is having this problem with mods dropping off crawmerax (noone else in room) on the 360 that seem too good to be true and then disappear.