I read in the apt.conf man page that the default apt pipeline depth used to be 10 (and remember seeing it in the past), so I set it to 10 in a couple of clients (localhost and another machine on the LAN) and had success with the apt-get update and about 50 megs of package downloads. I'll let the settings sit there for awhile and we can declare this problem a corner case and close it. If the problem reoccurs, I will reopen.
Thank you so much for your attention to this bug and your fine work on apt-cacher-ng! -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org