When a New Event is created, what can cause another Send Email with Options days later ?

[SunnySchindler]

How to troubleshoot subsequent Send Email with Options days later for "When a New Event is Created" ?

Could the cause be one of the following:

1. same Event get created again?
2. subsequent Send Email with Options because recipient of Email did not respond?

How to:

1. find out how same Event get created again?
2. build Flow to prevent sending same Email ?

My Approvers are frustrated to receive redundant Email for Approval days later.