When Charles is running the error disappears, when closed it returns

Question

Ok so I am trying to fix a issue where IE8 gets pushed into compatibility mode by something on the homepage and I cannot reproduce it in a local environment. I used Charles to map local the site's css file and narrowed the issue to a font that was being loaded. When I took the font out of the css, things seemed to be fixed. So I deployed the change.

When I was sure everything was deployed the issue was still happening. So I opened Charles to try to break down the html and see exactly where the issue was coming from but when Charles is open and running with Windows Proxy the issue disappears. I have turned off all other settings and tried throttling on a few different levels.

Has anyone else run into this kind of thing? Thanks

Answer 1

The reason might be because you have No Caching setup and it might be messing with your headers.

HOW IT WORKS

The No Caching tool prevents caching by manipulating the HTTP headers that control the caching of responses. The If-Modified-Since and If-None-Match headers are removed from requests, Pragma: no-cache and Cache-control: no-cache are added. The Expires, Last-Modified and ETag headers are removed from responses and Expires: 0 and Cache-Control: no-cache are added.