Hi Conor,
Before moving on, I want to confirm the issue is that everyone will send a meeting request to all the users in this meeting automatically when the meeting has been scheduled.
If this is the case, to help resolve the issue, I want to collect the following information:
1.Does the issue appear in Outlook or OWA(Outlook Web App)?
2.Does the issue appear when a specific user send a meeting request or all the users send meeting requests?
Additionally, please check if there are some transport rules or policy rules to make the issue appears.
Thanks,
Linda Wang