Steps to reproduce the issue

Task scheduled to run in one-month intervals at 10:00 (not with cron UI).
Scheduler running from an external cronjob every minute.

Expected result

At task run time, task executes and completes successfully like it does with Run Test.

Actual result

At task run time, task executes, but gets stuck in a loop where it seems to restart every 6 minutes. See log entries below.
To work around, click the "man running" icon, which stops the task, and click Run Test, which works.

#
#Date: 2024-10-20 15:19:12 UTC
#Software: Joomla! 5.1.4 Stable [ Kudumisha ] 27-August-2024 16:00 GMT

#Fields: date time priority message
2024-10-20 15:19:12 INFO Running task#03 'Email the newsletter on the 20th of every month'.
2024-10-20 15:25:13 INFO Running task#03 'Email the newsletter on the 20th of every month'.
2024-10-20 15:31:08 INFO Running task#03 'Email the newsletter on the 20th of every month'.
2024-10-20 15:37:04 INFO Running task#03 'Email the newsletter on the 20th of every month'.
2024-10-20 15:42:11 INFO Running task#03 'Email the newsletter on the 20th of every month'.

System information (as much as possible)

Joomla! 5.1.4
More info can be provided if necessary.

Additional comments

I don't recall any prior ticket for this, but since there are changes coming in 5.2.0, this will get another chance on 20-NOV-2024 after the 5.1.4 site is updated to 5.2.0. This issue is not reproducible on demand. Shorter (than one month) duration intervals tested seem to work fine.

I'm guessing this has something to do with the namespace in which the task executes, which is likely different when executing from a cronjob and not during an administrator session.