Sorry, on my hotspot I do not have such a high load.
Regarding my reported problem: It is interesting, that you have no problems. I re-tested, and found same problem under various conditions always to appear, in case either hotspot is activated, or web-proxy. So it might be something regarding the "universal proxy" scheme, MT uses.
To be shure, that you really NOT have this problem, too, can you please do following test:
(having web-proxy/upstream/transparent proxy enabled on RB), go to
http://messages.finance.yahoo.com/Stock ... of=1&frt=2
type a message, then click "Post Message"
On my system, error from squid shows up.
In case, you still do not encounter my problem, please post your version of squid, you are using. And version of RoS. That might be an issue,.
Thanx in advance.