To solve this, you need to run a few powershell commands on Exchange:
1. Open a PowerShell(as administrator) with the Account/Exchange Admin account:
Sign in to the Exchange Admin console (https://admin.exchange.microsoft.com/) and click on the Cloud Shell Icon on the top right:
OR
Sign into Azure Portal (https://portal.azure.com/) and open the cloud shell from the top right icon:
If you don’t have an account, create a free account with the Account Administrator login.
OR
You can also access Exchange Online Powershell from a Powershell console on your local computer. Follow the instructions provided in the Microsoft Article Connect to Exchange Online PowerShell | Microsoft Docs
2. On the shell, enter the following commands one at a time (Replace <roommailid> with the room resource email id):
Install-Module -Name ExchangeOnlineManagement
Import-Module ExchangeOnlineManagement
Connect-ExchangeOnline
Set-CalendarProcessing -Identity <roommailid> -DeleteSubject $False – AddOrganizerToSubject $False -DeleteComments $False
For more information, please review the Microsoft documentation available at Exchange Online PowerShell