On the WP site I am developing, there are a number of ACF fields the user can optionally fill out. However, when a field is left empty, with DEBUG on, this PHP notice is displayed:
NOTICE: wp-content/plugins/advanced-custom-fields/core/fields/text.php:148 - Undefined variable: format
as well as:
NOTICE: wp-content/plugins/advanced-custom-fields/core/fields/text.php:152 - Undefined variable: format
Not a huge deal, but it would be a lot cleaner without these notices.