Hi all :) regarding the close vote on Requests coming in the wrong order over the network
it has been closed as "not networking related", but we've pretty much excluded application-level causes and there's a useful comment from a user stating that he had similar experiences with certain HP routers. From our perspective the client is now doubting something called "ISDN simulator" that they have installed on the sites in question.
I believe that the "off-topic" close vote was premature, that there are cases when networking equipment or setup will cause such issues and that the potential answers could be useful to the community in the future and save some people days and days of ghost hunting - like myself.
The broader question is, "how do you know for sure that a highly specific topical bug isn't network related until a couple opinions come in from people who may have come across it".