Battery short causes message problems

My battery hold down had lost the moveable j-hook unknown to me. Over time the hold down bracket part over the battery migrated towards the positive terminal.

This was not properly noted when first the battery was recharged.

Messages appeared. The first related to the O2 sensors/or the catalytic converter.
A later message related to low voltage issues (reasonably enough).

After the battery had completely discharged, and the short issue discovered and corrected, upon re-start, the messages disappeared and have not re-appeared.

Mystery messages seem to have been solved.