Thanks for responding. No, we’re not. This is on WordPress 4.9.8.
So the fields are being displayed – they’re on the form, and are visible when you first load the page. But when certain actions in the Edit Post screen trigger acf.screen, all fields with a class of acf-postbox are hidden. Then, only those contained in the json data are unhidden again.
Fields registered in PHP don’t then get unhidden, and remain on the page with an inline style of display: none that has been applied by the ACF JS.
This is all behaviour from acf-input.js, and you can see it starting around line 10858.
