I've been using wp-json steadily for a couple years now on a headless CMS project and had no problem getting valid JSON back. I set the website to auto-update all themes, plugins, and WP version. I also added some extra plugins to enhance the wp-json:
- WP Rest Api V2 Multiple PostTypes
- REST API Helper
- Custom Post Types
Today, we started getting invalid JSON back with an "lea" prefix string on the beginning of the JSON for some unknown reason, creating invalid JSON. When I remove this "lea" prefix at the beginning of the JSON, the website works normal again.
Where might I look to see where this "lea" is being added?