The problem might have something to do with your role during the history of the respective submission(s). I have observed that you are blocked from unpublishing if you were involved in the history of the particular submission; it does not help if you are a journal manager.
PS: Similar issues have been discussed in other threads:
Editing past issues (May 2021)
Editing back issue in OJS 3.1.1.2 (July 2018)