PHP Fatal error while editing woocommerce emails

Hi, a fatal error happens when editing the woocommerce emails with the new (alpha) wc email interface.

This is the full stack trace log: https://pastebin.com/Qg9cv0th

This issue appeared months ago and it still present today with the lastest woodmart/woodmart-core version installed.
In that condition I need to go to /wp-admin/admin.php?page=xts_theme_settings&tab=estimate_delivery_section and then global disable Estimated Delivery by switch off the toggle, so I can go back to woocommerce email and the email previews works again.

Thank you.