Calendar custom alerts keep disappearing

I am trying to schedule a series of emails using the Automator paired with the Calendar.

I create the new mail message and save it to the computer using Automator.

I create an event for the day the email should be sent out, and select Custom Alert, then choose the automator file from the computer as the "alert".

All looks great:

As soon as I click out of the Event information, the alert disappears and defaults back to "none":

This keeps happening over and over and over and I cannot figure it out.

I have changed the type of Calendar I am sending from, I have tried other days, times, automations, and NOTHING will stay in the field.

Hopefully someone can help?

Thanks!