Using Classic Outlook on Windows for personal email, calendar, and contact management
Hello John,
Based on my knowledge, it is default behavior that the room mailbox's calendar show the organizer's name instead of the subject because AddOrganizerToSubject and DeleteSubject are set to True. If you want the room calendar to show the subject, you can run PowerShell to do that, and the steps are as follows:
1. Open Windows PowerShell and connect to Exchange Online PowerShell using a Microsoft 365 admin account.
2. Then run the following command to set the value of AddOrganizerToSubject and DeleteSubject to false:
Set-CalendarProcessing -Identity <RESOURCEMAILBOX> -DeleteSubject $False -AddOrganizerToSubject $False
After that, you will be able to see the meeting subject in room calendar. Note: Only new meeting requests are affected. For more info about this behavior, here is an article for your reference: Resource mailbox's calendar shows the organizer's name instead of the subject in an Exchange Server environment.
If you need more help, please feel free to let me know.
Regards,
Seven