There was a timing issue when two requests for the same URL hit at the same time.  The result was that the thread that created the connection didn't end up grabbing the wait lock and, thus, the connection didn't exist for the one that did.
There was a timing issue when two requests for the same URL hit at the same time.  The result was that the thread that created the connection didn't end up grabbing the wait lock and, thus, the connection didn't exist for the one that did.

No idea if this is the right solution, but it appears to work in my testing.

afilipovich/graphite-web,afilipovich/graphite-web,afilipovich/graphite-web,afilipovich/graphite-web,afilipovich/graphite-web