Cron never firing off pending jobs

Cron used to work, but after a re-install in (the same bare metal k8s cluster that housed it previously) it’s not, and I don’t know how to diagnose why. Cron is generally running within drone, but never finds anything to run:

{"level":"debug","msg":"cron: found 0 pending jobs","time":"2023-03-11T22:48:05Z"}

Let’s take an example. The drone UI shows that it’s scheduled:

weekly-rebuild master 0 2 0 * * WED 3/14/2023, 8:02:00 PM

… but that date/time will quietly pass, without triggering the build. It’s been vexing me for weeks now.

If I use the API or drone CLI tool to try to trigger that directly:

client error 404: {"message":"Not Found"}

and, in the drone logs:

{"cron":"weekly-rebuild","error":"Not Found","level":"debug","msg":"api: cannot find commit","name":"node-app-base","namespace":"jorj","time":"2023-03-13T11:28:59Z"}

So, what commit is it complaining about there? How do I go about repairing that fault? I’ve tried deleting and re-adding the cron jobs via the API, makes no difference. Builds run normally if I trigger them from the UI or via

drone build create jorj/node-app-base