I had the symlink arguments backwards.

06_workspace_mount.sh

@@ -38,7 +38,7 @@ if [ -d /home/${USER}/workspace ]; then
   fi
 fi
 
-ln -sf /home/${USER}/workspace $workspace_dir
+ln -sf $workspace_dir /home/${USER}/workspace
 
 echo "Mount the workspace"
 su - "$USER" -c "/usr/bin/java  -cp .:${workspace_dir}:${workspace_logdir}/ -Dlogback.configurationFile=${workspace_logdir}/logback.xml -jar $workspace_fuse_jar $SHINYPROXY_OIDC_ACCESS_TOKEN $workspace_dir" >/dev/null 2>&1 &