Manually running
$ sudo /usr/share/software-center/update-software-center
seems to have made the problem go away. Looks like this may have something to do with software-center's xapian cache under /var/cache/software-center/.
BTW I did make a backup of /var/cache/software-center/ before running that command, in case that's useful for debugging.
Manually running software- center/ update- software- center software- center/ .
$ sudo /usr/share/
seems to have made the problem go away. Looks like this may have something to do with software-center's xapian cache under /var/cache/
BTW I did make a backup of /var/cache/ software- center/ before running that command, in case that's useful for debugging.