We have implemented interstitials (pop-ups) on a website (Business Articles Website). The popups are basically used for getting leads from the website (using Signup popups).
Before Popup implementation the traffic was steady, After the implementation, the traffic started to decay after a couple of weeks and due to the drop we disabled the popup from the website and initiated a force crawl and within next few weeks, we observed traffic gaining back to its normal trend.
Within these timelines drop in desktop traffic was more and mobile traffic remain steady. As per Google guidelines, interstitials are more likely to be affected on mobile than desktop. But in our case, desktop traffic was hit more than mobile. So we carried out this experiment for 3 months. And we observed traffic decay and regain.
Is interstitials the only culprit here (as the drop is only in desktop) or Can there be some other reasons as well for the traffic drop?