Hi guys
Elliot here – ACF dev.
Sorry about the recent ‘acf/save_post’ and $_POST[‘acf’] issues.
I’m aware of the problems and have fixed the (ad re-uploaded the plugin files).
Please be sure to checkout the known issues guide here: https://www.advancedcustomfields.com/resources/known-issues/
Please re-download the plugin files, or await 5.6.1
Thanks
Elliot