I have been noticing this for months. Sorry I haven't reported it until now.
When I click "Delete Cache" in the admin bar, it doesn't seem to actually clear the cache, but if the "Delete Cache" button on the Easy tab is clicked, it does clear the cache as expected.
I've tested this whenever I've made changes that included changing a site build number in the footer. After uploading those changes, and clicking "Delete Cache" in the admin bar, the page footer info doesn't update on a refresh in a separate browser. So I then go to the Easy tab and click "Delete Cache", and voila, the page footer updates when I refresh that page again.
Has anyone else run into this?