Currently I am seeing incorrect ad sizes on some of my pages. The ad unit is supposed to be a 120x600 unit in the right hand sidebar but certain pages are showing 468 width ad units - it does not look geeat for the page layout ;)

I have checked the code on the page and it is correct in all cases - it's just that the incorrect frame is being returned. These incorrect ads also show with the default adsense ad colours.
The ads / pages have not been hijacked and contain the correct publisher id and ad code.

Here's the ad size as specified in the html
google_ad_width = 120;
google_ad_height = 600;

Here's the start of the iframe layout
window.google_render_ad();</script><iframe width="468" scrolling="no" height="60"

Anyone else seen anything like this?