Error when updating an event using multiple attendees

Hi everyone,

We have an issue related to the Attendees field on the Event object. We have a flow that creates an event with multiple attendees, utilizing the Event Relation object to add additional participants. 

However, we have encountered an error when attempting to update the Event record using another flow. The error message is: "This error occurred when the flow tried to update records: INSUFFICIENT_ACCESS_OR_READONLY: Only event organizers can update this field".

We cannot understand the problem since we are running the flow with the same Admin user who is owner of the events.

Please find the screenshot of this error in the attachments.

Thanks in advance!

@Mauro Lunghi @Lorenzo Sopino @Lorenzo Sopino