Diff Publications doesn't report different VTs as different. If you do a diff between http://www.isfdb.org/cgi-bin/pl.cgi?100 and http://www.isfdb.org/cgi-bin/pl.cgi?308447, diffselect.cgi will show the two pubs as identical even though pub ID 100 includes http://www.isfdb.org/cgi-bin/title.cgi?42872 ("by Mary Gentle") while pub ID 308447 includes http://www.isfdb.org/cgi-bin/title.cgi?189644 ("as by Mary R. Gentle").
Anonymous
Fixed in biblio/submitdiff.py 1.6, installed in r2014-66 on 2014-01-25. Closing.