A likely cause is that the Request is being updated more than once during the state transition, causing the notification to be evaluated more than once. This could be coming from a Business Rule, Flow, Workflow, or integration.
I would first check the two sys_email records to confirm whether both emails were generated by the same notification or by different notifications. I would also check the Request's history to see if multiple updates occurred even though the state appears to have changed only once.
For the notification configuration, if the intention is to send the email only when the Request reaches a specific state, I would use request state changes to <state> rather than just request state changes, and disable the Inserted option if it isn't required.
I wouldn't rely on Weight alone to resolve this, especially since the current notification has Weight 0. The key is first determining whether we're dealing with duplicate record updates or multiple notifications being triggered.
