The user with the most recent text edit was being credited with the upload. This is fixed in the next release for new uploads. Existing uploads will still be wrongly credited. Unfortunately the name of the correct uploader is unavailable to restore it. Thus, this has been promoted to Priority 1 due to data loss of the uploader's name.
Additionally, approving moderated uploads was never actually updating the current version of the file. Similarly, approving moderated edits or uploads was not removing the edit lock from the page. This is now fixed in the next release.
Because of this, an upgrade script is necessary to detect and remove any locks.