I'm pretty sure it is in here: mount: improve implementation of --daemon mode · Issue #5664 · rclone/rclone · GitHub
You could try the workaround from there which effectively does the --daemon in bash before launching rclone.
echo "Starting Mounts ..." && sleep 5 && bash -c 'setsid sudo rclone mount --allow-other --dir-cache-time 24h --vfs-read-chunk-size 124M --vfs-read-chunk-size-limit 4G --buffer-size 512M --vfs-cache-mode writes Cloud\ Storage\ Server\ 1\ Uncrypt:/ /mnt/Cloud\ Storage/Cloud\ Storage\ Server\ 1/ </dev/null &>/dev/null & jobs -p %1' && echo "Done..." && sleep 5