Remove_source_branch push option not working


We have GitLab Enterprise Edition 14.3.6-ee.

If I create a merge request using:

git push -o merge_request.create -o -o merge_request.remove_source_branch -o merge_request.merge_when_pipeline_succeeds -o merge_request.title=Blah

The merge request is created, to the correct target branch, with the correct title, with the merge-when-successful behaviour … but the source branch is not scheduled for deletion after merge.


What am I doing wrong?