Devices routinely appear to go out of compliance after a period of inactivity. IE end user doesn't tur on their device and connect up to the outlook app for a period of time.
The question I have is what length od time for the device to disconnect from the service and ni emails are recieved to the device.
After sync'ing the device in the portal/workrplace and sometimes 2FA kicking in the device has service restored to it.
Can anyone tell me if this time period is set anywhere within the console or preset by Microsoft?
The timeout your referring to is defined in the MAM Policy:
Try changing the Timeout in the "Recheck the access requirements".
Another policy you can manage in Conditional Access is how often it will evaluate if the device is still compliant or not - the default is 30 days.