I also experience this. ACF hides Page Attributes and even some Field Groups on save. It doesn’t remove them, you can re-add them from the Screen Options at the top.
I reinstalled WP and it works now. I don’t know what could have happened. Thank you anyways. It looks like it wasn’t the error of ACF. Cheers.
I did so. Still no errors. I made a screenshot. The field in the middle should be a wysiwyg.
