Issue
Incorrect condition on the business rule which fires the event specified on the email notification may send duplicates.
Cause
When there is an email notification defined to run when a specific event is fired, and the business rule which fires the event has an incorrect condition specified, it will skip that condition and evaluate the remaining, if any. This may lead to send out multiple notifications.
Resolution
In a use case example where there is a Business Rule on the [sys_history_set] table with the Advanced Condition:!current.id.demand_manager.changes() && (current.updated != previous.updates)
Notice the second part of the condition which has:current.updated != previous.updates
There is no "updated" field in the "sys_history_set" table. The correct statement should be:current.updates != previous.updates