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                12:44 p.m.
            
        Dear Henrik.
Have you able to figure out the issue you had[1]. I had similar (in your case certain mailing list, but in my case every lists on some domain). I made smtp log level: debug.
What I find is,
Using agent: <mailman.mta.bulk.BulkDelivery object at 0x7f8cac5b55c0>
When lists works it appeared on log. On failing I couldn't find this.
--a