Two intact boys - 16 and 4. Neither has ever had any problems at all. DS1 wasn't retractable when he stopped being naked in the public parts of the house - call it 8 or 9. I assume he is now, but I don't know for sure. DS2 has been retractable for about 6 months. He thought it was a great "trick". He hasn't had any problems, though...and considering some of the things I've seen him stick in there, I wouldn't be surprised if he had!
Also, my 46 year old brother is intact. To the best of my knowledge, he's never had any problems, either. I don't think he has, as at least one of his ex-girlfriends had major boundary issues, and I know far more about that aspect of his life than I ever wanted to. Ugh.
I honestly had no idea until I came to CaC that some boys/men did have problems - major or minor - with their foreskins.