The runner shell script is using a bashism, namely $RANDOM:
https://github.com/basho/node_package/blob/develop/priv/base/runner#L309
but the runner script is using /bin/sh which on many systems is not bash and thus $RANDOM is undefined:
https://github.com/basho/node_package/blob/develop/priv/base/runner#L1
Something portable would need to be used in place of $RANDOM.