If up2date hits a package during the download phase that is already cached, eg because /var/spool/up2date is shared, or from a prior up2date being killed before finishing installing it prints Gtk-CRITICAL **: file gtkprogress.c: line 518 (gtk_progress_set_percentage): assertion `percentage >= 0 && percentage <= 1.0' failed. for each such package. This seems to have done no actual harm
heh, lovely warning
This is fixed in the 7.3 errata.