I don't get it.
According to http://www.monetizemore.com/blog/best-ad-sizes-for-mobile-devices-in-2015/, Google would label a URL as mobile-friendly if it believes it is mobile-friendly.
When I check my pages through page-speed insights, I never get a complaint about mobile usability issues except for issues related to elements in adsense ads themselves. Issues I receive from page-speed insights that all pertain to ads are "Size tap-targets appropiately", "Minify Javascript", "Leverage browser caching". Some of these issues change depending on the ad that is loaded.
Is it possible that a mobile site with adsense ads could cause google to believe it's not mobile-friendly when users search for the site online? Or am I just over-thinking things?