Git subrepo commit doesn't add commits to subrepo history

Question

I'm using git-subrepo.

I've cloned a repository as a subrepo into another with git subrepo clone, then I've created a branch with git subrepo branch since I realize I cannot run git subrepo commit commands without it.

git subrepo clone subrepo_url my_subrepo
git subrepo branch my_subrepo
git subrepo commit my_subrepo -m "My message"

I did some commits and when I execute any of the next commands to consult the subrepo history (as it's described in the documentation):

git log subrepo/my_subrepo/fetch
git log refs/subrepo/my_subrepo/fetch

it only shows subrepo commits previous its cloning in the parent repo.

Is there something wrong or missing with my process?