I have been experiencing this myself, but for a lot longer period of time. It doesn't always happen, but comes and goes. Sometimes, switching to another page and/or refreshing the page clears it up. I don't know what causes it, but I'm trying to track it down because it bugs me too.

Occasionally, on an idevice, I zoom out so the text is bigger and the ads are hidden. Never had a problem with this in the past. Now, the screen often snaps back to full screen so the ads are displayed. In other words, zooming the display doesn't work.

Is this a new Google ad requirement to get more (irritated) eyeballs to look at ads?