I started a magazine-type website in the beginning of January. I had adsense on it, getting a cool 2% CTR on desktop and 1.6% on tablets. Then one day, overnight, something strange happened: CTR on desktop tanked to 0.5% where it still is to this day. This was two weeks ago. Happened overnight. My only explanation was that a seemingly minor change introduced a bug that crashed lots of desktop browsers. However if this were the right explanation, then the average number of pages per session should have tanked at the same time, which didn't happen. So at my completely lost. Any suggestions on why this might've happened and how to fix it?