I doubt there is a bug, I’m not seeing an issue. Something else must be causing the issue.
Look in the database in the wp_usermeta table. Find the meta key of “_is_premium_customer” the meta value of this should be the field key of the ACF field. If this value is missing or is not the correct field key then you need to find what is altering this. It could be anything, or some filter. Then you need to start deactivating other plugins and maybe switch the theme to figure out what is conflicting with the saving of the acf field key reference value.
