Hi gebeer,
Yes, the article's title was based on the original art_title field, then I changed it to use a custom text field storing it's content inside title at com_content table. Was this then?
I managed to recover the situation by running insert queries on cck_core which restored the relationship between id, cck, pk, storage_location, author_id and parent_id. Fortunately it was a few dozen articles, not hundreds... ;-)