I am the beneficiary and I have nothing, no blemishes whatsoever, my case still pending. I have a friend that had to wait much longer than most for his approval, also no issues just USCIS taking their time.
Don't hate me for saying this but in my humble opinion USCIS just doesn't have a good process in place, that's why we have cases from many months before June pending, hundreds of June cases still pending, and they're working and even focusing on July these days. We can come up with theories but I won't do that.
Again, just my opinion, but if you haven't done anything crazy in the past, anything that will cause your case to be denied, you'll just get approved eventually either directly or after an RFE etc. I doubt even USCIS knows when, just need to be patient!