I'll resist the temtation to ask, "beer?"
You say you've been bulking. How much have you been eating (portion size) and how often? 1 gm of protein per lb. of bodyweight? Spread over 6 meals during a day?
I was having trouble eating so I started adding junk food for a few weeks - hamburgers, chips and fries. That stuff is gone from my diet now. I'm still bulking for another month so I'm not counting calories or anything, but I'm definately eating over 1 gram protein/lb of LBM plus at least that in carbs, plus fat from mostly peanuts and a small amount of junk still in my diet.
I'm pretty sure my abs are overdevloped, because even ripped my gut isn't really small. Given their development an some fat they already are going to stick out some. I feel that I might be experiencing some sort of bloating, because the gut sticks out more sometimes, randomly.
I have also heard of fat that resides under the abs, but am not sure how to know if that is what is going on or what I can do about it.