Problem occurs while using Pixture Theme and goes away when I switch to Garland. Tried changing width to 100% but problem persists.

I have a few category terms set up at the same level in the taxonomy heirarchy.

Authors (term 4)
- Author #1 (term 39)
- Author #2 (term 40)
- Author #3 (term 50)

When I do taxonomy/term/39 or taxonomy/term/50 - the page draws correctly with a nav bar on the left and the content window on the right.

When I do taxonomy/term/40 - the left nav bar drops below the content section.

I have looked at the html source for 39 & 40 at the point where it transitions past the node teasers, the pager and into the sidebar-left div and can see no differences. There are no differences in the way the terms are defined.

I saw a reference to a similar problem related to DHTML in http://drupal.org/node/361888 - but the DHTML module is not installed here.

I am using Taxonomy Access, but none of these terms have been touched there.

Any idea what may be happening here?

Update, I have added several new categories. Problem occurs in some categories, others not. Sometimes on first page, other times on all pages. May have something to do with whether an image (of a certain minimum size) is in one of the teaser items.

Thanks in advance.