As of Friday last week we have been experiencing duplicate emails being sent despite there being only 1 email action in the workflow. The workflow is only running once (we have checked Workflow History).
We are using External sending. The email step is taking a long time to process (4 minutes) and sends multiple copes. A "Log Workflow History" before and after this step shows that the step itself only runs once.
When we switch to Internal sending the email step runs in less than a minute (likley seconds) and only 1 email is sent.
Is there an email issue on the Nintex side when external sending is being used?
Does it happen only in 1 workflow?
Make a simple test with another Nintex Workflow and with a Sharepoint Designer workflow?
Perhaps is a problem with your external sending
I am also suddenly seeing a similar behaviour on an EU tenant (where workflow notifications come from neu.workflownotification.com). In multiple workflows, emails are often (but not always) received in triplicate (2 immediately and another about 2 minutes later). The workflow starts only on Create Item and logging clearly shows it running only once. Interested to know if anyone else is experiencing the same?
Update: We have continued to experience this issue recently. We were down to 2 emails per 1 expected. Then last week things started to behave properly with only 1 email received. This morning, we have received TEN (one per minute) emails for every time the send notification action has run (only once). It was previously suggested by support to add a pause at the beginning of the workflow, that was done but has not helped.
This is not a normal behaviour, I've dropped you a DM regarding this as it is something that the product team can investigate for this tenant.