After running ALTER EVENT event doesn't run event for single run

This fault was first observed on our AWS RDS instance running 10.5. Following an update to 10.6 the problem appears to still be present, so I thought I'd create an account here and raise it as a bug as it may warrant further investigation and/or fixing. It may equally not be a bug, but the behaviour doesn't make sense.

First, Create an event to run once at some point in the future.

CREATE DEFINER=`user`@`%` EVENT `adhoc_query_runner` ON SCHEDULE AT '2026-01-10 00:30:00' ON COMPLETION PRESERVE ENABLE ... etc

This event then runs ok and is preserved.

When the event is altered for running again at a later date/time it then doesn't run at the allocated and altered time. No errors are logged.

ALTER DEFINER=`user`@`%` EVENT `adhoc_query_runner` ON SCHEDULE AT '2026-01-20 00:30:00' ON COMPLETION PRESERVE ENABLE ... etc

The only way to run this event again is to DROP it and CREATE it again. The ALTER EVENT works fine in our environment with other events that repeat on a schedule. It is only this style of EVENT where there is no schedule and it is only to be ran once at an allocated time.