Workflow rule not working correctly every time

Workflow rule not working correctly every time

I have a workflow rule set up that is not working correctly every time. The Criteria is the same for every ticket that it should work for.

Execute on:
Create

Criteria:
Subject contains Bounced agent email
AND

Actions:
Set the fields to:
Category: Leads
Sub Category: Bounced lead/email
Due Date: 2 days

Sometimes the actions are set. I thought it might be because the tickets are being created outside our business hours, but some tickets outside our business hours have had the actions set.