In the RetainWorker logs, one of the final entries for each user is the "DateFlagManager" (see an example below).  Request that you add the user's e-mail address to this section.  Finding which user this DateFlagManager relates to is harder than it should be.

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03:40:11, 245[RTWQuartzScheduler_Archive_Worker-1] [DEBUG] DateFlagManager: ^M
Last archived mail Retention date=Sun Feb 14 00:31:01 EST 2021^M
Last mail before first error mail Retention date=Wed Dec 31 19:00:00 EST 1969^M
Max mail Retention date=Sun Feb 14 00:31:01 EST 2021^M
Mailbox login time=Sun Feb 14 02:00:11 EST 2021 ^M
Date Chosen:Sun Feb 14 00:30:01 EST 2021