Duplicate entry warnings on content creation

Hey everyone,

I'm running Drupal 6.14 with CCK 6.x-3.x-dev (2009-Dec-07) and Content Taxonomy 6.x-1.x-dev (2009-Sep-13) solely for the multigroup module.

I've created a content type with a multigroup field, combining two content taxonomy fields: Role, a select list & Person, an autocompleting text field.

When I create a new instance of this type, I get the following error:

* user warning: Duplicate entry '35-0' for key 1 query: INSERT INTO content_field_role (vid, nid, delta, field_role_value) VALUES (35, 35, 0, 68) in /var/www/qhist/sites/qldpastonline.library.uq.edu.au/modules/cck/content.module on line 1277.
* user warning: Duplicate entry '35-0' for key 1 query: INSERT INTO content_field_person (vid, nid, delta, field_person_value) VALUES (35, 35, 0, 150) in /var/www/qhist/sites/qldpastonline.library.uq.edu.au/modules/cck/content.module on line 1277.

This happens for both new and existing terms. The new instance is being created correctly; the fields & their values display properly on the node view, and both fields' values are findable via Solr. So it appears to be working, I'd just like to avoid this warning if possible.

I was initially using CCK2 and have only just upgraded to CCK3; could it be an issue with the existing data created by CCK2? I'm at a point where I can easily restart the site fresh, if that would help with this issue.

Any help would be greatly appreciated.

(I initially posted this in the CCK issue queue, but it was suggested to raise it here as well...)