I'm already easily amused, but I like that one in particular.Quirk in Quark.
A bit surprised a new account would do the same thing. Especially if you cleared all of the font cache files on the system.
Did you perchance launch FAP in the new account? I know a lot of folks like it, but I personally am not thrilled with that font manager. It tries too hard to control the system fonts, and you don't even get to choose if it does or not.
If you did use FAP in the new account, remove the test account and create a new one. Login to that and go directly to Quark and see what it does. If you still see the same thing, you'd probably have to reinstall the OS.
As a side note, I know people go both ways on this, but I never, ever install an new OS over an old one. I always create a new partition and install the OS clean, then install all of my third party apps from scratch. The only things I will bring over from the other partition are some preference files so I don't have to set those up again for busy settings apps like Photoshop. I do this as I have time and continue getting work done in the previous OS. Then switch over after I feel things are working as they should.
Compared to the slew of issues I see reporting on Apple's forums when they upgrade the OS, I literally never see 1% of the issues others complain about.