MgBetaDeviceAppManagementTargetedManagedAppConfiguration can create, but not update?!

[dannyKBjj]

Update-MgBetaDeviceAppManagementTargetedManagedAppConfigurationApp @params only works if you do not include 'apps' in the hashtable. Otherwise you will get the error:

"Update-MgBetaDeviceAppManagementTargetedManagedAppConfiguration : Cannot apply PATCH to navigation property 'apps' on entity type 'microsoft.management.services.api.targetedManagedAppConfiguration'.
Status: 400 (BadRequest)"

New-MgBetaDeviceAppManagementTargetedManagedAppConfigurationApp @params works fine, so presumably this is a bug.

Used graph explorer to investigate:

https://graph.microsoft.com/v1.0/deviceAppManagement/targetedManagedAppConfigurations//apps/

retrieves the apps just fine.

There is another URI https://graph.microsoft.com/v1.0/deviceAppManagement/targetedManagedAppConfigurations/{targetedManagedAppConfiguration-id}/apps/{managedMobileApp-id}

It isn't obvious how to retrieve a valid {managedMobileApp-id}, but tried some app Ids retreived from the previous graph request (e.g 'com.asana.app.android') and also some bundleIds, but it comes up with:
"No OData route exists that match template ~/singleton/navigation/key/navigation/key with http verb GET for request /MAMAdmin_2412/MAMAdminFEService/deviceAppManagement/targetedManagedAppConfigurations

probably not surprising as i'd expect it to be a guid? However, there seems to be no way to retrieve a valid Id.

Graph explorer did reveal the Update-MgBetaDeviceAppManagementTargetedManagedAppConfigurationApp cmd-let, but that won't work without a valid {managedMobileApp-id}

Also tried retriving an Id using Get-MgBetaDeviceAppManagementMobileApp

$mobileApp = Get-MgBetaDeviceAppManagementMobileApp | Where-object {$_.AdditionalProperties.bundleId -eq "com.asana.Asana"}

Same problem...

Can anyone help?!