You said this was happening in Chrome too. Is that still the case?
Anyway figured out when I have it the modem in RAS mode it does it all the time, when I have it in NDIS mode it stops doing it most of the time. I don't know what it is about this forum that trips it though, perhaps ISP recompression buggery is breaking pipelining or something.
I've still only encountered it on this forum, so I assume its something that wouldn't be easily fixed (would probably require a whole lot of messing about with network tracing and I'm not really up on that stuff.)
I'll have to check if it's still doing it on the new code though