There are two main reasons why email templates might look weird in your inbox:
1. Form fields have been changed. When building a custom email template, you have the possibility to use codes correspoding to form fields. These fields insert user input into the message. For example, if you use the code [%Name%], this will be replaced, in the actual message, with the form user’s name. Now, if you change form fields, the codes change accordingly, but the email template stays the same (with the old codes), which makes it impossible for it to work properly.
Whenever changing form fields, be sure to make any necessary changes to the custom email template.
2. The email template belongs to another form. Custom email templates are stored in the same place, irrespective of the form they have been built for. In other words, when you create a new email template for a particular form, you’ll be able to view it in the Email Templates list of any form in your account.
Be sure not to apply the email template created for a form to another form. You can give templates suggestive names, so as to remember quickly what forms they belong to.