Fix for the backoff issue is in the pilot.  Observe very few backoff errors over the last few days, though still non-zero.  (Also there are some jobs that throw the backoff limit error but are still marked as finished, not failed, which I don't understand.). Thanks to Fred and Michal for following up!  Discussion is continuing on GGUS and JIRA.

Tape downtime due to NESE tape system maintenance.

Issue where a pool that had IO blocked due to a kernel panic caused a lot of job failures.

Blacklisted the weekend after Thanksgiving, slow recovery due to HC test 1293 not submitting a new job.