EffectOwner$ use is sometimes problematic

[tool4ever]

An example would be the delayed trigger from Endless Whispers: Nimble Obstructionist allows you to counter it, but you should still be the controller

(Currently you might not be able to target it, but that is a different problem: #1229)

Also it's missing OneOff$ to prevent it from triggering again after it gets countered. [^1]

For these reasons it might be cleaner to rewrite such cards into DelayedTrigger directly?

[^1]: Teferi's Time Twist also has that problem (if it wouldn't be missing Duration$ Permanent anyway), but that param can't be used there because the RE needs to stay