apehater: i made a quick search on the forum about that and it seems to me that the overlay problem is only galaxy related? i don't use galaxy
A bit belated - no, the "Game overlay" issue is a side-effect of the latest site revamp, hence not restricted to Galaxy. I had it (not using the client), and it affected the total game count (increased by one), but an account refresh restored things to what they should be (both on the library page, and in the acount-tab drop-down menu).
Perhaps you had it, but didn't know you did, and only noticed the change in the total game count after an account refresh?
If you're sure this wasn't it, then you'd have to go over your library, and check if a title is indeed missing, and which one. Or if you have a recent backup list (via MaGog, for example), you could get another one and compare them.