SOLVED!
One of our team tracked it down to the Wordfence settings option ‘Monitor background requests from an administrator’s web browser for false positives’. If the box is checked it enables logged in administrators to monitor real-time background (Ajax) requests made from the front-end. That’s what adds the non-accessible code to the front end pages. Two ways to avoid the accessibility problem: either
1) un-check that Wordfence option for the ‘front end website’ and save or
2 simply log out of the back-end before running the accessibility check. (Using a completely different type of browser for admin logins will avoid the need to keep logging in and out).
I am having the same problem. Has Wordfence come up with a solution please?
