A bug was introduced by http://trac.webkit.org/changeset/55153 - which has some broken MIME logic. Patch coming.
Created attachment 49556 [details] Initial Patch Very simple patch.
Comment on attachment 49556 [details] Initial Patch Clearing flags on attachment: 49556 Committed r55299: <http://trac.webkit.org/changeset/55299>
All reviewed patches have been landed. Closing bug.