After upgrading to DXA, we are experiencing significant delays when publishing to live site

This issue creeped up after upgrading to DXA. Prior to DXA, pushing pages to the test server and live server happened very quickly. You could see the updates in the browser without long wait times. Now with DXA in place, publishing to our test server is still quick but after publishing live, it can take several hours before you can see page edits in the browser. The tridion publishing queue claims that the publish is successful immediately. The nature of the edits are often minimal (just text and image changes). Ideas on what could be causing this?