Overriding activation email with theme works with tutor dev but not tutor local

Hi all, as per the title, I have tried overriding the activation email with a theme

theme/lms/templates/student/edx_ace/accountactivation/email/body.html

This works with tutor dev but when I build the images for tutor local, the custom activation email does not show, despite the file being correctly copied into the openedx image with the rest of the theme files.