By default, the Exchange Online settings delete the meeting details from invitations sent to room mailboxes. Apply the following PowerShell commands to the room mailboxes of all shared mode devices that you enable for the Hybrid Calendar Service:
Set-CalendarProcessing -identity "room" -DeleteComments $false
Set-CalendarProcessing -identity "room" -DeleteSubject $false
Set-CalendarProcessing -identity "room" -AddOrganizerToSubject $false
If you want to be able to forward invitations scheduled from outside of your Microsoft organization to the device, add the following command:
Set-CalendarProcessing -identity "room" -ProcessExternalMeetingMessages $True