I've narrowed the problem (on my end) down to 'GameGuard' that happens to be running when I'm playing Phantasy Star Online 2 (an MMO, Japanese-only but with an English patch).
GameGuard is notorious for interfering with anything and everything that runs alongside PSO2. It prevents/blocks Ventrilo/TeamSpeak from running as well as messing with anything else it can.
So far I've avoided the worst of the issues, the only problem has been that I can't browse the internet with GameGuard running (so far).
In my specific case, it causes the browser to hang and then when I close PSO2 (and GameGuard) it finally shows a dialog asking me if I want to 'stop scripts' on that page.
This isn't a bug report so much as a general info-dump to let other people know to check their computers for GameGuard, Akamai Network Services (malware), Pando Media Booster (also malware), or other such 'random' 3rd-party programs they may not be aware of.
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