I've been running into some unexpected and strangely consistent HTTP/1.1 504 Fiddler - Receive Failure, and when looking into the response I see a the X-ServerSocket value to be two values:
X-SERVERSOCKET: REUSE ServerPipe#1321REUSE ServerPipe#384*NEW*
This would seem to imply that the two server sockets were used for the connection, this seems bizarre. Are there conditions where this should happen?