title: Browser is automatically adding a <s> tag into html error
body: <p>I'm customizing a <a href="http://webdesign-finder.com/dotdigital-marketing/" rel="nofollow noreferrer">dotdigital WordPress theme</a> on a client's domain <a href="https://www.247btl.com/" rel="nofollow noreferrer">247btl.com</a>. I've been making a few style changes, and middle of it this error popped up. Below each section browser is adding <code>&lt;s&gt;</code> tag.</p>
  
  <p><a href="https://i.stack.imgur.com/ZafTD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZafTD.png" alt="error-screenshot"></a></p>
  
  <p>I reverted back to the original stylesheet, but the error persisted. Any ideas. Thank you.</p>