Today via the PowerShell cmdlet 'Update-AzWvdSessionHost', an administrator can assign a user to a session host without the user being assigned to the applicationgroup. This can cause some confusion to administrators if they are able to perform this task as the user will not be able to see the host in the Windows App. The suggestion would be to either put in a check which denies the assignment if the user is not associated with the applicationgroup directly or indirectly via group association. Or, update the cmdlet to also add an assignment to the application group by adding a required parameter which would assign the user to the application group.
It's a small tweak but it may help with the overall stability of the Desktop.Virtualization PowerShell stack. Thanks!