Does the layers update change how Thousand-Tailed Watcher's -3 power effect works? Specifically, is the effect retroactive or does it snapshot?

Ruling: Thousand-Tailed Watcher's -3 power effect is a snapshot that only applies to units in play when it resolves. It does not continuously check or apply to units that enter play afterward.

Sequence:

• Watcher's effect resolves and reduces the power of all current units by 3 (to a minimum of 1)
• The effect stops checking after it resolves
• Units that enter play after Watcher resolves are not affected
• If an affected unit is later buffed, it simply adds to its current power (no retroactive recalculation)

Nuances:

• Hidden units are not affected because they are not in play when the effect resolves
• The layers update does not change this snapshot behavior; it only addresses issues where later layers affect earlier layers (like Fiora's might reduction affecting her traits)
• Other similar effects like Grand Strategem work the same way (snapshot, not continuous)