As mentioned by Brian Thies in the comments below, Hotmail have now released an update to their platform that fixes this bug, therefore designers don’t need to take any action to update their code. We’ve run a few tests through Hotmail and the symbols are now being displayed as normal.
We’ve noticed a peculiar rendering issue that’s just appeared in Hotmail – the © ASCII code used to insert a copyright symbol loses all formatting. We’ve run some tests in various live browsers, and the issue seems to appear in IE, Firefox and Chrome/Safari. It appears that the symbols are actually being replaced by Hotmail’s own emoji images, for example: .