Ok, I know the cause...it's WP-Super Cache. I am just wondering if it is possible to tie into their API to clear the cash for a produce once the sale ends? I think they have such a feature set in their API. I was just doing a site check to make sure everything was up and running, and I noticed a few products that still listed an expired sale price. It only went away when I cleared all the cache. I'm sure there are plenty of other WooCommerce users using a caching plugin to keep the store peppy...so if this happens with me, I would assume it happens to others.
Is such an update possible or is there a hook?