I've tried these Mac browsers and found no problems: Mozilla, Safari, IE 5.2 (I think), and Camino and everything appears OK on them.
FYI: There is a bug in the Printable Version view. It doesn't parse bbcode. It's supposed to be fixed in a Monday 'Bug Fix' release according to their Bug Tracker thread... There are a number of issues - I've alread fixed a few - such as the uploading of attachments problem, but they often don't post the details fix.