Um... that was no help at all. The reason I wanted YOUR profile was because for most of the rest of us, the signatures are not updating because the stats are not updating. So... it's for the same reason as half the other superfluous threads being opened in this section every day, as has been mentioned over and over, and explained over and over, and for which there is a big red box at the top of every player's stats page: for any player who has played Special Forces, the EA feed is screwed up, and NO stats are updating, nor will they until EA fixes their feed, and no one here works for EA and can give that answer.
Now, if, as you say, your stats ARE updating, but your signature is not, then that WOULD be something new (at least to me) and worth investigation. So... unless you provide your player profile, I can't know that, and can only assume that like everyone else, you need to find the "search" button. ;P