Hello, Marie,
According to the next facts :
1/ Our email builder works fine with basic WooCommerce emails in test mode and in real mode;
2/ Our email builder has the option to choose an email template and it supports 3rd-party plugins emails templates;
3/ You have created a template for email of 3rd-party plugin and it works fine with Edit mode but not with live mode;
After checking all those items above we should ensure you that the problem is with that plugin code/files path/etc. According to our support policy, we do not and can’t provide support for 3rd-party plugins -> https://prnt.sc/l6jgQReibzG8
So, you should anyway contact with plugin’s author on free support forums or directly to plugin’s author email.
Thank you for understanding.
Kind Regards,
8theme team