When an iOS or iPadOS device has a passcode enable, it is locked by the native Data Protection each time the device is locked. It will remain in Data Protection mode until the passcode is either entered locally or cleared via MDM command Clear Passcode. While the mobile device is locked and Data Protection mode is enabled, it will only accept certain commands from the MDM server.

When a device cannot perform a command due to situations like this, it sends a NotNow status without performing the command." Jamf Pro reflects this NotNow status as "device is busy - will try again."
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Per Apple's MDM Protocol documentation, under the Error Handling section on page 27, there are certain times when the device is not able to do what the server requests and it sends a NotNow status without performing the command.

The following commands are guaranteed to execute in iOS, and never return NotNow:

• DeviceInformation

• ProfileList

• DeviceLock

• EraseDevice

• ClearPasscode

• CertificateList

• ProvisioningProfileList

• InstalledApplicationList

• Restrictions

This means that any commands outside of the ones noted above can be expected to return the "Device was busy" response, and remain as a Pending command until the device is next unlocked.

The Update Inventory command we send from Jamf Pro contains the following commands, executed in this same order in quick succession.

• SecurityInfo

• InstalledApplicationList

• ManagedApplicationList

• CertificateList

• ProfileList

• ManagedMediaList

• ProvisioningProfileList

Of these commands InstalledApplicationList, CertificateList, ProfileList, and ProvisioningProfileList are commands that can complete while a device is locked, and we will often see them as individual Completed Commands on device inventory records in Jamf Pro if a device installed an application or completed another task in-between it's previous and next full Inventory Update.

However, because SecurityInfo, ManagedApplicationList, and ManagedMediaList are not MDM commands that can complete while a device is in Data Protection mode per Apple's documentation noted above, the Update Inventory command cannot complete when an iOS/iPadOS device is locked by a passcode.
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To avoid facing the Not Now/Device is Busy response, we would need to restrict and prevent passcode on iOS devices which is not a recommended security practice in most device use cases.

If we are receiving the response currently we can:

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