I'm trying to find out why a change ticket notification contains an additional Change ID #. 

Here's the Subject line from the email sent to change stakeholders (change exiting the Deploy stage):

Subject: #CH-1661#Change ID: ##CR-1661## has been successfully deployed

Here's the subject setting under the 'Stage and Status' section: Stage (Deploy) --> Status (Completed) section:

Change ID: ##CR-$ChangeID## has been successfully deployed

Where is that first CH ID # coming from?