Slackware :: Mutt Doesn't Recognize Mailcap Setting?

After the new year I updated my -current to the latest, and now mutt doesn't recognize my mailcap setting for text/calendar attachments. In ~/.mailcap, I have

text/calendar;korganizer -m %s

and in mutt, .ics attachments are recognised as mime type text/calendar. It's always worked like that. Now, however, mutt is just paging the .ics attachment to the screen.

I've checked the content of all other mailcap files listed in mutt's mailcap path, and ~/.mailcap is the only one with an entry for text/calendar (in fact, ~/.mailcap is the only file in the path that exists). Mutt does recognise my image mime types (eg. image/jpeg;mutt_bgrun geeqie -t %s).

I can import the .ics attachment by hand by saving it to /tmp and running 'korganizer -m /tmp/file' manually. That takes a slight moment to respond (KDE bloat? :-)). When I try opening it from mutt, there is no delay before it pages the file, so I don't think it's even trying korganizer first.

I can't remember changing any configs recently, which is why I'm suspecting something in a recent Slackware update must have affected it.