Git: interactive rebase lists incorrect (too many) commits

I fixed this by doing a rebase with master first and then for the rest of the commits

git rebase master
git rebase -i HEAD~n

It depends on how your git tree looks like. A "merge" commit for instance can have two or more parents. Depending on this, your commit can have multiple grandparents.

You probably need to rebase with

git rebase -i HEAD^1^2
git rebase -i HEAD^2^1
git rebase -i HEAD^2^2

(one of these three).

See here for more details about git's relative commit notation.