Welcome to the forums
Erm.... I dont think is much of a problem. did you have a set-back message or anythin?
Jus though, it also could be that he DIDNT blocked you, and when you signed in, for some reason h displayed it for a secod, but then you appeared offline to him. Therfore, he clicked on you, doesnt say anything because you look offline now, its grey because you've blocked him/her. I think that makes sense