Bard's ult on Butcher's Bridge didn't put turret in stasis

I was in ARAM with Bard and I hit level 6. Shortly after, two of my teammates tower dived and I decided to ult the turret to save them. My ult launched normally, The enemies hit were put in stasis, and the turret, while having the stasis particles, continued firing and dealing damage, leading to a wonderful Annie quadrakill. I was on the red side and the blue outer turret was hit.