Message is not displayed correctly when Send Test Email

When testing out the emails that get sent by the system (using Send Test Email), the message shortcode does not get processed properly, and causes duplicate text in the end email.

My message email consists of:

Test
<p>
This is a test of the message: (message)
<p>
Thank you!

When I click on the Send Test Email button for that email, I see in the modal dialog box that the text looks the same (see pic).

When I receive the email, I see duplicates that look like this (see other pic as well):

Test

This is a test of the message: Test

This is a test of the message: ******

Thank you!

Thank you!

My assumption at this point is that if the message is NULL or undefined or whatever, whatever is parsing the message isn’t handling the condition correctly. I haven’t setup the test with a real message (I’m just starting to work with this PP theme).