This happens if the name of the upstream branch and local branch do not match, which sometimes happens, and usually is unwanted:
> git status
On branch release-1.2.3
Your branch is up to date with 'origin/master'.
To solve this, run:
git branch --unset-upstream
Then, once you run git push
again, you will be asked to use the --set-upstream
option to set the upstream branch correctly.