Why is my meeting room showing organizer’s name instead of the meeting subject?

If the meeting room shows the meeting organizer's name as the meeting subject, instead of the meeting subject entered by the organizer, your O365 administrator will need to update the mailbox resources default properties with the commands below. These changes should only be made by authorized administrators.

# create a PowerShell remote administration session and update properties 'AddOrganizerToSubject', 'DeleteSubject' and 'DeleteComments' to $false for any RoomMailbox type mailbox
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri <https://outlook.office365.com/powershell-liveid/> -Credential $UserCredential -Authentication Basic -AllowRedirection
Import-PSSession $Session
Get-Mailbox -RecipientTypeDetails RoomMailbox | Set-CalendarProcessing -AddOrganizerToSubject $false -DeleteSubject $false -DeleteComments $false
Remove-PSSession $Session