Workflow Only works in Sandbox

I'm having trouble with this workflow. 

It's a simple workflow that's based on a TRANSACTION with a subtype of SALES ORDER.  The status is RELEASED and it's set to execute as an admin.  It's set to initiate ON CREATE with a trigger type of AFTER RECORD SUBMIT. 

The workflow has 1 state.  That state has 1 action.  Send Email.  The emails is set to send from ME to ME.  The Trigger is AFTER RECORD SUBMIT.  The event type is CREATE.  It's got one condition, a formula that checks the transaction quantity against a formula. 

This workflow works as expected in the Sandbox.  It works when I create the transaction and when other people create the transaction.  The exact same workflow does NOT work in our production copy.  I can pull up transactions that should have triggered the email, and they show that the workflow was triggered, but the emails are not being sent.  I've checked to make sure they're not ending up in my spam filter or junk mail folder.  They're just not being sent.