I posted this as a Bug here but apparently it is intended behaviour as a of right now.
The situation is this: I have a master project and multiple other individual projects. I have Rules to automatically copy tasks created in an individual project to the Master project, which is a great use of Rules. However, I would also like categorization to happen to rules in the Master project, for example to mark new tasks as “Not Started” and to assign them to me. At present, a task that is added to the Master project by a Rule will not trigger Rules in the Master project that change status or assign them. For assignment, I can work around this by including individual Rules in each individual project, but there is no workaround for changing status, since only the Master project has a Status field (and you can’t share a field across projects).
I recognise the danger of creating infinitely looping Rules, but having them silently not trigger is both confusing and very limiting in terms of what Rules can do. I think that setting some limit on the number of cascading triggers would prevent infinite loops, or some other method of detecting them directly.