Joomla! Update Notification Scheduled Task failed, exit code 5 after upgrade to Joomla 5.4.0

The Scheduled Tasks list looks like on all websites with 5.4.0 installed.

Expected result

Should work as in Joomla 5.3.x

Actual result

When i run a test:

the test is also not saved in the logs or Execution History

System information (as much as possible)

All my websites with 5.4.0 installed
All websites which are not updated work fine.
This happens across different hosting environments, different PHP versions, and different servers, so it doesn’t appear to be host-specific.

Additional comments

It looks like something changed in the scheduled task handling or in the update notification plugin since Joomla 5.4.0, as the issue is consistent across all environments.