Not all fonts have this symbol. So if you don't specify a font explicitly, the browsers try to use a fallback-font to display things. And IE may use a different fallback-font.
I'm not sure if you can call this a problem with IE. It could be a font problem: the font which IE tries to use, may incorrectly tell the system it can display the sign, while it actually can't.
So if you know which fonts can display the rupee, specify one of those fonts in the HTML for it.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
