I figured it out myself.. But just in case somebody else has this issue...   The problem was the file permissions of the two replacement (discussed in this bug report: https://github.com/SpaceinvaderOne/Macinabox/pull/49 ) files after they were copied into the Macinabox Docker container.  When you pull them using wget, the permissions get set to your user's default and then when you copy them into the Docker container they have the wrong permissions (most notable the "unraid.sh").