I’m an end user and not an expert but from what I understand APO started heavily caching all pages of our website a couple of days after aktivation.
As a result first the post views in front end did not update anymore.
Then it become worse. All users become unable to login to our site anymore (fontend login).
After I disabled Automatic Platform Optimization (APO) all went back to normal.
I thougt APO would improve Pagespeed by serving fronts from Cloudflare Edge Network and I nowhere read about this heavy page caching.
Big warning to all users, do not aktivate APO on a live site without prior testing. It will cache your site to death.