twentyten hosted theme displaying incorrectly

The twentyten theme is displaying incorrectly in Chrome. Looks OK in Firefox and IE. This happened the other day. Some suggested clearing cache would correct, which it did. But why is this happenning? It now happened again.

Sites: http://themattwalshblog.com/
http://diaryofdennis.com/

Guessing that some won’t see the problem so here is a screenshot:
https://www.flickr.com/photos/7343736@N06/13509676414