I've discovered a conflict when Conditional Logic is used to limit visibility of a meta box to a specific page, and the same meta box contains a required field. For example, meta box is visible when
post_ID = 25.
Editing that specific page is fine. But since Conditional Logic hides the meta box (and its fields) on other pages, those pages can’t be updated, because the required field for those pages has no value.
Maybe this is by design, since Conditional Logic doesn't truly eliminate the meta box on other pages, it simply hides the meta box from view. (Although checkboxes for hidden meta boxes still show up in 'Screen Options' at the top of the page.)
For now, I removed the required attribute on any fields in meta boxes that use Conditional Logic for visibility. Is there another way around this?