Underlying code showing on live page

http://redeemer-kenmore.org/ A few weeks ago, some of the underlying PHP code started showing at the very top of our pages, mostly hidden by the menu on a laptop, but very noticeable on a smart phone. Upgrading the PHP version from 5.6 to 7.1 did not solve the problem. No new plugins have been recently installed. Of course, existing plugins are constantly updating. This code does NOT show on the AMP version of the website. Thanks for any help you can provide. Bob Chapman