The error:
http://wordpress.local/wp-admin/post.php?post=433712&action=edit net::ERR_INCOMPLETE_CHUNKED_ENCODING 200 (OK)
For the past several months, Before I updated ACF to a version after 5.5.13, I would get the above error in my local environment. Restarting nginx/php-fpm/varnish or restarting the vagrant instance would not fix it. However, I could reliably get rid of it by disabling ACF entirely.
Even more frustrating is the fact that the problem will go away on its own for hours/days/weeks. It is a truly intermittent problem, but persistently intermittent :/
However, I recently updated to the latest ACF version and discovered my Custom Fields were gone in wp-admin. I discovered this was being caused by ACF version 5.5.13. I added the below code to my installation and BAM the ERR_INCOMPLETE_CHUNKED_ENCODING error returned. Removing this line (i.e. hiding Custom Fields) causes the error to go away. Until now, I’ve not been able to reliably produce the error so effectively.
/* Unhide Custom fields which ACF hides in 5.5.13+ */
add_filter('acf/settings/remove_wp_meta_box', '__return_false');
I’ve googled this quite a bit. There are an awful lot of “red herrings” out there. Namely, changes to nginx buffering, php.ini changes, etc. None of these works.
Looking for some help. Cheers!