hannamyluv - 2:52 pm on Oct 25, 2013 (gmt 0)
I did. But during a cross browser test for other changes on the site, we had found that a version of AdSense we were testing was causing the JS on the site to fail catastrophically in a few browsers.
Once we changed the AdSense code, CTR (and EPM) returned to normal.
It may or not be the case with your site, but worth a running it through a cross browser tester (for both PC and mobile) to see if this may be an issue on your site.