GitLab has remediated an issue in GitLab EE affecting all versions from 16.11 before 19.2.8, 19.3 before 19.3.5, and 19.4 before 19.4.2 that, under certain conditions, could have allowed an authenticated user to approve a merge request despite having contributed commits to it, due to improper identity resolution.
Upgrade to versions 19.2.8, 19.3.5, 19.4.2 or above.