node add or edit override panel page saves a blank taxonomy despite selections.

When I create or edit a node using a panel overriding a node add or edit form, I can change the category selections (those loaded from an existing node appear fine) but when I save the node, all my taxonomy selections are obliterated. I get an empty taxonomy array on my node object. This applies to node edit and node add panel overrides. However, I can change the body and teaser and title and other content values. The taxonomy is the only thing that seems to break.