Why does that matter? IIRC it was wunderground.com and a couple of other sites. Since I deleted those fonts, the error has not recurred. I'm positive they were the root cause, at least on my system.
It matters because it may let us identify a misbehaving font (and fix-it eventually). The weather underground website you mention makes no use of any of the fonts I did upload. To display its iconic glyphs you need: http://fonts.wxug.co...ation-icons.ttf.