The problem: ads look like this in Firefox 33.0.2 running Adblock Plus 2.6.5 with the site http://www.apkmirror.com
1. The ads are responsive AdSense ad units (not regular ones), which may be important for the diagnosis.
2. Adblock Plus not disabled everywhere, just this site.
3. If I disable Adblock Plus everywhere or disable the add-on, the ads load fine.
4. If I restart the browser with the site open, it'll load the ads fine when it restores tabs after restart. However, after refreshing the tab, the ads will get messed up again.
I conclude that the issue is with Adblock Plus somehow blocking an element or elements on a whitelisted page or rearranging them which confuses the AdSense code and it serves responsive ads possibly without knowing the area it's allowed to serve in anymore (or with an area that doesn't match the real area and is much smaller).
Any ideas or fixes?