Contribute Adding Extra Code on Publish

One of our clients is using the Mac OS X version of Contribute 4 to make changes to the following webpage:

http://www.earlswantsyou.com/all-about-earl/who-is-earl/index.html

Making a simple text change to the centre column (main content area) and Publishing causes the following code to be added to the sidebar menu on the left:

<ul style="margin-bottom: 0;">

I've tried changing the user settings so that only text changes are permitted, but it doesn't make any difference.

Has any else seen this (or similar) behaviour? Any workarounds to share?

Thanks for reading and for any assistance you're able to provide.