Francois,
This article was written prior to V4, and one of the first things I noticed about V4 is that the phenomena did not replicate. There are still regularities to be noted across prompts, I am sure, but "characters" like Ms. Midjourney appear to have vanished, for sure. I find that a bit heartbreaking, to be honest. It does, however, highlight the question about what causes any such patterns in Midjourney out similar programs to occur.
I'm going to continue trying to learn about the technology and hopefully someday I'll get answers. I'll try the random-string approach as well. I wonder how much we can learn about what goes on inside these programs by poking around on the outside? It's an interesting question to pursue.
J