Reminds me of this old classic:
Openoffice can’t print on Tuesdays
Openoffice can’t print on Tuesdays
Cause was another job that hammered IO because reasons, so mine was being killed by some unreported IO timeout after 1min, and retried the next minute (so every other minute). The other one was scheduled to run on off business time (weekends and Monday before people get to work) and had some burstiness that made the IO go down enough every other minute which allowed my short-execution one to proceed.
top was silent because IO, took us a long time to even thing about iotop because the failure was non obviously tied to IO.