It's not too early to tell, we knew from the beginning that the use of Signal (let alone its clone) was not authorised to be used for such communications.

Yes, there's a fleet of people who are supposed to make such tech decisions. The people involved specifically went against those rules. The existence of a group chat using an authorised app is a violation on its own, adding a journalist to it is a violation on top of a violation.

Adding a journalist was accidental, but using such an app (despite it not being approved) is very intentional.