Interesting. Mal, that situation is exactly what Rick Astley described here:
To me it looks as if the page isn't loading all elements prior to it displaying. What I mean by that is it doesn't seem to be applying the styles properly.
The whole page has loaded, but the stylesheet has been ignored, or not loaded.
You're going to have to let me stew on this one, while I try and think of a reason this is happening to you.