Hi,
This is why your Node-RED updated to the latest version using the script that you installed with this link DockerIOT/nodered/docker-compose.yml at main · fragolinux/DockerIOT · GitHub
This will update you to the latest version ... image: nodered/node-red
Mine has .. image: nodered/node-red:3.1.3
So that solves your mystery why your Node-RED changed 
Yes as I mentioned I had been trying other versions like 4.0.1 and 4.0.0 and gave up. I then tried 3.1.3 as you suggested and all came good.
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