notifications on-rollout-completed comes twice or 3 times

[azopat]

Hello, I have my trigger defined like this
triggers:
trigger.on-rollout-completed: |
- oncePer: rollout.metadata.annotations[“rollout.argoproj.io/revision”]
- send: [rollout-completed]
But the notification on rollout completed regularly comes in duplicate or even 3 times on slack channel. Any idea how i can investigate it ? we are on argo rollout version 1.2.0