Editing node with freetagging terms generates DB error

Haven't had time to investigate where it's choking, but taxonomy.module tries to RE-insert tag associations for freetagging taxonomy terms whenever a node is edited. That generates the following error:

Warning: Duplicate entry '361-384' for key 1 query: INSERT INTO term_node (nid, tid) VALUES (384, 361) in /home/viaposit/public_html/jeff/includes/database.mysql.inc on line 108

..Repeated once for every free tagging term. Nodes with 'normal' taxonomy terms don't experience the error.