PKP PN accepts deposits but no published issues are ever queued for preservation (OJS 3.5.0.5)

Dear PKP Community,

I am the Managing Editor of Sustainable Trends and Business Research (STBR), and I am experiencing an issue with the PKP Preservation Network (PKP PN).

Journal:
https://journals.researchapt.com/index.php/stbr

Issue example:
https://journals.researchapt.com/index.php/stbr/issue/view/7

Article PDF example:
https://journals.researchapt.com/index.php/stbr/article/view/59/33

System information:
• OJS version: 3.5.0.5
• PKP PN plugin: Enabled
• Journal Identifier: Assigned
• Terms of Use: Accepted
• Network Status: “The PKP PLN can accept deposits from this journal.”
• Online ISSN: 3007-0414
• Print ISSN: 3007-0406

The issue:
Although the journal has been correctly configured for more than one year, no published issue has ever appeared in the PKP PN Deposits table. The table always remains empty (0 deposits).

What I have already verified:
• The journal is fully Open Access.
• All issues are publicly available.
• PDFs are accessible without login.
• The PKP PN plugin is enabled.
• The journal has a valid PKP PN Journal Identifier.
• OJS scheduled tasks and background jobs are enabled.
• The issue has been published for several days, and previous issues published months ago also never appeared in the deposit list.
• There are no PKP PN-related failed jobs.

I would appreciate your advice on the following:

  1. What conditions trigger an issue to be added to the PKP PN deposit queue?
  2. Is there any log or diagnostic tool that can show why no deposit jobs are being created?
  3. Could this indicate a server-side issue with PKP PN, or is there another configuration that I should verify?

Thank you very much for your time and assistance.

Scheduled task logs are being created for ProcessQueueJobs, which confirms cron/scheduler activity. However, there are no PKP PN / PLN / Depositor logs in files/scheduledTaskLogs, and the PKP PN Deposits table remains empty.