Different behaviour of rebase -i

hi,

While doing a git rebase with my upstream branch ahead of my local
branch, first git rewinds my local branch to point to the upstream and
then prints "Nothing to do". As expected, my local branch ends
pointing to the upstream head.

But when I use the same command with the same branches using git
rebase -i, nothing happens  and my local branch does not point to
upstream (the behaviour is different).

Is this different behaviour of rebase -i expected or is this a bug?
This is still happening in git version 1.6.0.2.443.g52e83

br,
-- 
// leo