After noticing in my google webmaster tools that my test site is getting some 404 errors, I have noticed some strangeness in my store. The following link can be found on the bottom two pages..

Pages that link to
http://test.italianhampers.co.uk/ind...products_id=15


This link correctly takes me to a product I recently built (A box in my gift packaging category)
http://test.italianhampers.co.uk/ind...products_id=15

This link takes a user to the same product but incorrectly in the "preserves" category...I have not assigned this item to be a member of more than one category.
http://test.italianhampers.co.uk/ind...products_id=15

Can anyone explain how this has happened?

Recently rebuilt this test site using new 1.5 fresh install and new database.