https://github.com/singularityware/docker2singularity/blob/master/docker2singularity.sh#L255

This is not a valid way to transform a CMD or ENTRYPOINT. From the Dockerfile documentation:

RUN has 2 forms:
RUN <command> (shell form, the command is run in a shell, which by default is /bin/sh -c on Linux or cmd /S /C on Windows).
RUN ["executable", "param1", "param2"] (exec form).