cbc-pillowfight generates coredump on illegal command line options

I'm trying to reproduce MB-23347 locally and tried to paste the command line provided in the bug report by using libcouchbase installed from homebrew (libcouchbase-2.7.2.sierra.bottle.tar.gz).

trond@ok:1008> cbc-pillowfight --spec couchbase://127.0.0.1/bucket-1 --password password --batch-size 1000 --num-items 25000000 --num-threads 24 --min-size 1024 --max-size 1024 --populate-only
libc++abi.dylib: terminating with uncaught exception of type cbc::BadArg: Unrecognized key: usernm
zsh: abort (core dumped) cbc-pillowfight --spec couchbase://127.0.0.1/bucket-1 --password password

It seems a bit aggressive to generate a core dump if the user provides an unknown command line option... (that being said, I can't even see "usernm" being provided)