Workflow Notification Triggering Twice

Hello all,

I normally use email notifications versus workflow notification to trigger emails, but for this catalog item I trigger a notification from the workflow to notify the requestor the request has been approved. I use this method because I need to send to multiple users in addition to "opened by" and "requested for". For some reason the emails keep triggering twice and I've noticed that this is only for the notifications triggered through the workflow and not regular email. Does someone know what may be causing this?

Thanks in advance!

Grace