Just had a PVP match against Coulson and C4rol. C4orl laid photonic barrage, i stunned her when there was 1 left on the tile. next turn Coulson’s passive version of Best Laid Plans reduced the Photonic Barrage tile to 0 and it fired while C4rol was still stunned and downed one of my characters.
Is this working as intended?
Yes. Coulson, Hood, Green Goblin (and other characters I may have forgotten) can reduce the timers on the countdowns of stunned characters (and possibly even airborne characters; I have not tested this). If they reduce the timer to 0, the tile expires and has whatever effect it has.
That is working as intended. If an ability forces a countdown tile to 0, that countdown tile will trigger it’s effect (If it has one) even if the character who placed it is stunned/airborne. Granted, if that CD tile heals the caster and the caster is airborne, the caster will not be healed and the CD tile would have been wasted by the ability.