The archiver updated the document row inside a transaction and then waited on media.lock. A concurrent file move holding media.lock and updating the same row could deadlock with it, and the unique archive filename was generated outside the lock from an instance loaded before the parse.
The archiver now acquires media.lock before opening its transaction, refreshes the document under the lock, and moves the archive and thumbnail inside that block, so it never waits on media.lock while holding the row.
stumpylog
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