It was just the .gitlab-ci.yml file I was thinking about. It’s not completely clear to me exactly how your rules work, or why all the other pipelines run when your variable is set.
It is quite common on this forum for people to ask questions about their .gitlab-ci.yml file, and many people will include the file, or part of it, often with many details removed, just to demonstrate the issue that they are asking about. For example, this question that I asked a couple of years ago contains a very small part of a much larger CI config.