Not that HTML validation is a driving goal, but the HTML filtering in the template system for Litmus currently refuses to interpret & properly. This should be fixed, and should probably be fixed in such a way that all such entities (&*;) display correctly.
The Template is actually one-upping us here. It is translating unsafe/ambiguous chars into their entity equivalent so that, e.g. & in the database becomes &amp; in our display. The easy solution is to do a database search and replace for HTML entities to change them back to simple characters and simply let the Template system do its thing.