Some Public Pages not Public

Suddenly, there are a number of pages in a very large site that should have public access but now require to be logged in to view with the S2Member message: Sorry, but you do not have permission to view this content.
All the pages’ settings indicate that the page should be publicly visible.
It’s not all pages and I can’t figure out what is causing this.

Well, maybe I’ve found a fix with updating Advanced Custom Fields plugin. This seems to creep back after I find a workaround but now seems to be working. Any similar experiences on your end?