git bug?

hello,

Using .git/info/exclude file to ignore some of my directories, I notice a curious think I took for a bug :

I wanted to exclude all except that is inside my /TED/ directory I wrote a file exclude first as this

* !/TED/

but this doesn't work and is dangerous because no warning, and git status said (after I realize commit and push on server) working copy is clear. fortunately looking at repository I realize the mistake and trying a "git add" tells me there is something wrong in the exclude file I changed it as this

/* !/TED/

and it works but I don't know exactly why  Have you a begin of answer ?

thanks a lot in advance for any answer