Well, long story.
Docker 19.x changed the whole structure of the docker info output.
We fixed that when 19.x was still on the beta branch more than a month ago at https://github.com/discourse/discourse_docker/commit/98c5fec43de299bdfc55970cea3495fa4c27d6ac. The fact that our launcher script auto-updates makes this a non-issue for most people.
However, our launcher script checks for the storage compatibility before auto-updating. So people who have an old launcher and update docker before updating launcher can get into that state.