A null, string or number in the canonical {"jobs": [...]} list reached
every reader: the due scan raised AttributeError on each tick, so no job
fired, and list/resolve crashed too. Drop the junk with a warning and
self-heal the file, as the id-keyed map flatten already does.
(cherry picked from commit 2e2438d160967392184b2193cfc2e2ca124c2b7a)