What web pages and what characters is this happening on?

If I come across one again, I will post a link.

But I find it hard to believe that even MS would make as boneheaded a mistake as leave a ISO-8859-1 character out of the Unicode font.

Perhaps they did it on purpose to make Netscape/Mozilla look bad. MS has a habbit of "creative omission". For example, there are bugs in MS-Access that MS does not fix even after many versions have passed. They tell you to upgrade to SQL-Server if Access "cannot handle it". You can do this if you are your only competition.

Note that IE will render the same characters correctly. Thus, it is appearently using a different translation table than Mozilla.