As talked with @basak-qcom,
When a release is made, there needs to be ONE commit which takes the debian/changelog file and replaces the UNRELEASED distro field and change it to unstable and tag this commit. This changelog field change commit needs to contain ONLY this change. The fact of thanging the UNRELEASED field to unstable is the release. Once this commit is tagged, we then push a following commit which puts back this unstable field back to UNRELEASED, which represents going back to 'work' on the next release.