[Mailman-Users] Automatic Unsubscribes

[J. Edward (Ed) Muns]

At exactly 7:00am on each of the past 5 days (31 May, 1-4 June), a different
batch of subscribers have been unsubcribed from a list I administer using
Mailman.  I receive a message from Mailman for each of them, but there is no
information about why they were unsubscribed or who initiated it.  I've had
this happen in the past with other lists I manage under Mailman.

What do you think is going on and how do I fix it?

Thanks,
Ed Muns