This issue is happening for us with WP_DEBUG turned on.
Wordpress 4.8 with ACF 5.5.14, has anyone else had a re-occurrence of this issue?
Also does anyone know what the problem was when fields are being declared in PHP as all of the ACF fields we use are declared within PHP so leaning towards this possibly being part of the issue.
The values are still being output to page so when wp_debug is not outputting to page you do not know its happening but as we develop themes / plugins with this setting turned on we would like to get to the bottom of the problem.
