Reminder and Escalation are not working as expected

Summary:

We want to set-up reminder email notifications for the invoices that are in ‘Initiated’ status and pending for approval.

If the requester doesn’t approve/ reject the invoice after 1st reminder, we want to escalate it to his/ her manager.

In dev3 we have done the setups for the reminders and escalations but are not working properly.

We have setup escalation for 5 level at each 30mins and reminder for every 5mins for testing purpose but it is not working as expected.

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Below are the expectation for testing, but it is not working.
A- Reminder email setup for every 5mins