This is a followup from https://moodle.org/mod/forum/discuss.php?d=409932.

It seems that the APCu cache is not available to the cron.php script. As a result it can end up pulling stale data. This is most notable with the admin notifications page as it reports that the cron scripts haven't been run when that have.

Steps to reproduce:
1/ enable APCu for your moodle instance (both web and cli)
2/ configure Moodle to store config settings (core/config in APCu) as the primary store
3/ Let cron run for a while then visit the notifications page. You will get a report that cron is not running correctly.