Right, I've done a simple test on all the major browsers on my computer. One thing I noticed is that resolution and the size of the window affects the skin position, as do some addons if you are signed in or out.
All the browsers were reset to factory settings with cache, cookies, add-ons and plug-ins on a Windows 7 computer at 1440x900
Firefox 6
Top ad and side ad are static.
1-2 pixel skin overlap.
Skin only loads the second time you load up the webpage in Private Browsing.
Internet Explorer 9
Top ad and side ad run.
1-2 pixel skin overlap.
Skin only loads the second time you load up the webpage in InPrivate Browsing.
Opera 11
Top ad and side ad run.
1-2 pixel skin overlap.
Skin only loads the second time you load up the webpage in Private Browsing.
Chrome 13
Top ad and side ad run.
1-2 pixel skin overlap.
Skin only loads the second time you load up the webpage in Incognito.
Safari 5
Top ad and side ad run.
No skin at all.
The effect seems to be different with other settings as Safari and Opera seemed very different (much like Are You EXPd) before a reset.
So a full factory reset of the browser may fix it...temporarily.