Problem with HTML Markup within FireFox

[ArchangelX]

I just started having this issue, but ONLY after updating Firefox to the latest version! So it's got to be on FF's end, something definetly changed. Before I updated, it was perfect! Some of my users are suffering from it as well.

I use some bit of custom coding, but it doesn't look like it's the code that's the problem. I use a bit of code in the Markup section of my Usergroups to indicate their membership level...and I'm getting this error (see attachment).

The code I use for the second markup box is this:

</b></font><img src="images/ranks/gold.gif" border="0" class="inlineimg" />

It only occurs to one or two people in a thread. Everyone else looks fine. Gotta be something wrong in the way FF is handling this.

Does anyone know what the heck is going on? Why would it show up way down there?

Thanks!

Mike K.