That seems to have done the trick. I haven't noticed the problem
recur, so far. My google searching kept finding things for Ubuntu that
lead me down the garden path.
[tim@localhost ~]$ uname -rsvp
Linux 4.13.5-200.fc26.x86_64 #1 SMP Thu Oct 5 16:53:13 UTC 2017 x86_64
Boilerplate: All mail to my mailbox is automatically deleted.
There is no point trying to privately email me, I only get to see
the messages posted to the mailing list.
I don't think it's pure coincidence that "officialdom" sounds the
same as "official dumb."