I've been working on trying to get a mobile theme working with google adsense and I'm having a tough time with ads 300 pixels wide or larger. I've tried the plug-in with jetpack mobile theme and I've modified the code for my purposes, but even before modified, if I tried the 320x50 size google ads or 300x250, the right side of the ads were cut off, even when I viewed the site with my phone in landscape where the width was well beyond 320 pixels. If I tried using the responsive ad code, all of the ads were cut off at about 300 pixels wide.
I don't know if this is an issue caused by the jetpack mobile theme or the way the plugin places the ads into the code.
If visiting from a mobile phone I have narrow ads which work above and below the content but I left a 320x100 ad above the comments which is cut off on the right to illustrate the problem I'm having.