BUG: Disrupting Shoal

Opponent's Field: 3 tapped forests, 1 tapped swamp, 2 untapped Viridian Emissary.
My Field: Martyr of Frost, Spellstutter Sprite, Ninja of the Deep Hours (tapped), 2 tapped Islands.
Opponent casts Green Sun's Zenith with X=3 (which is why all 4 lands are tapped). In response, I cast Disrupting Shoal, exiling Judge's Familiar from my hand (CMC=1) to counter Green Sun's Zenith (CMC=1). When Disrupting Shoal resolved, Green Sun's Zenith was not countered.
My Field: Martyr of Frost, Spellstutter Sprite, Ninja of the Deep Hours (tapped), 2 tapped Islands.
Opponent casts Green Sun's Zenith with X=3 (which is why all 4 lands are tapped). In response, I cast Disrupting Shoal, exiling Judge's Familiar from my hand (CMC=1) to counter Green Sun's Zenith (CMC=1). When Disrupting Shoal resolved, Green Sun's Zenith was not countered.