How to stop override email template content(response) on issue doctype

when i select one email template then i get proper response but after i select another email template the subject will change accordingly to the email template subject but the content(response) has override like i can view the previous as it is but newest one also with previous.

check the attached image screenshot.
help me to solve this.

Please raise a github issue for this.

Thanks for the reply,
ok i will.