If I understand you correctly your files now have wrong MusicBrainz IDs stored and thus get automatically matched by Picard to those wrong releases on the right pane, right?
If so you can either drag them to the left again or doable Picard moving them to the right at all by enabling the ignore MBIDs option in Options > General.
Then you can re-identify the tracks again, although this could end up to be not so easy. As the existing metadata is now likely wrong you cannot rely on the normal lookup, which normally gives best results. You have to treat the files as if they have no proper tags, which means using Scan (AcoustID search) + manual lookup and correction if you want to get the correct albums.