[2023] Hey Uhh... ANet, Why Does My Stunbreak Banner Not Stunbreak?

In the skill description it says that it breaks stun on initial placement, meaning that you need to successfully place the banner in the world for the stun break to occur and for the other boons to apply. It's more of a stun break for allies. If the stun break occurred before the banner was placed, it would create a situation where the banner could be cancelled before the cast finishes, putting the skill on the short interrupt cooldown (a 4s cd stun break) - which is obviously not intended. The solution there would be to have it go on full cooldown regardless of the outcome of the skill cast, meaning if that you were interrupted before it finished it would go on a full cooldown without receiving the benefit from the banner's boons. That would feel worse.