Make index fails with no entry for /usr/ports/audio/linux-c7-mikmod

[Mike Clarke]

curlew:/root# freebsd-version -ku
11.0-RELEASE-p2
11.0-RELEASE-p5
curlew:/root# make -C /usr/ports index
Generating INDEX-11 - please wait..--- describe.accessibility ---
--- describe.arabic ---
--- describe.archivers ---

[snip]

--- describe.x11-toolkits ---
--- describe.x11-wm ---
make_index: /usr/ports/games/linux-uplink-demo: no entry for /usr/ports/audio/linux-c7-mikmod

curlew:/root# ls -l /usr/ports/audio/linux-c7-mikmod
ls: /usr/ports/audio/linux-c7-mikmod: No such file or directory

https://www.freebsd.org/cgi/ports.cgi?query=linux-c7-mikmod&stype=all reports nothing found so what's causing make index to try to index it?

-- 
Mike Clarke