Hi,
I had a super clear example today, and I think I have seen it in the past: if a formula field includes a Today token, then the value on tasks will only update if the task or project is visited.
The problem is when you use that value in a Rule, like “field X greater than 1 > do Z” would only trigger when you visit the project. Kinda defeats the purpose doesn’t it?
Is this a bug? I hope so but I don’t believe so…
Sounds like a bug or a change because that is not inline with the expected behaviour when this feature launched.
I’m convinced that formula fields are essentially powered by rules in the backend so I’d be surprised if they don’t run everyday anymore.
Hmm, perhaps
I recognize that today() is updated once a day automatically as this post said.
I found an old knowledge entry in our knowledge base stating that we already saw that the above is not correct: a formula including Today will be updated only when a user visits the project/task… 
at the time we didn’t hear Asana say “this is a bug”… @Julio_V what do you think?