1. Reset All Emails to Factory Defaults to get back the default templates.
2. Add a backslash character to escape the double quotes before saving the email template.
Note: any previous customization made to the email templates may be reviewed from the sys-admin activity log.
This has been corrected in TPAM 2.5.915.
From the TPAM 2.5.915 Release Notes:
BFER 7583: Adding a double quote (“) to an email message body or subject line would cause a failure trying to save the email template.