I have a pretty minimal Drupal 8 install with some views blocks that show upcoming event node links. I've noticed that once an event is passed they still show up and it is because the pages of my site are cached. However, I set the "Page cache maximum age" on the performance page to 6 hours and Drupal continually caches pages for days or weeks. I have to manually click clear all caches before the site will update. Cron is also setup and running regularly without a problem. I thought maybe that triggered the cache rebuild but I've set it to 6 hours, 12 hours, 3 hours, etc. with no result.
I'm not sure why this is happening. I'm not doing anything else to cache, no other modules or server programs like Varnish or anything.