On request #2 and #37, the same asset host seems to be firing off two dns requests. Does that make any sense?
http://www.webpagetest.org/result/130619_NH_7e3cefd3e41ff40f83f905cd53a72dba/9/details/
It doesn’t make any sense to me unless you’ve tripped over a browser or instrumentation bug. I recommend capturing a tcpdump (advanced settings) and verifying that the requests are actually being issued and then see if there is anything in the responses that might trigger it (like a really short TTL).