From what I understand from the Helpdesk I just spoke to when a automated task such as sfc /scannow or dism commands occurs or even other tasks that require a system that does not need a restart the following applies.
1. Offline devices will try to perform the task when they start>>which is fine
2. Online devices that fail for example due to "pending other operations described above say needs a restart for updates" the task will fail and NOT try again.

Would it not be better to have the option on automated tasks to have a tick box for example "try task on devices that fail on next device restart" or some other mechanism for automated tasks.

Going on that devices fail you cant just keep running a task on everything to catch the failed ones and identifying them and just running on individual failed devices is a logistical nightmare