Poppy Bug? - Gamplay

This has happened twice in the last few days. I try to CC Poppy right as she casts Steadfast Presence and Heroic Charge, and the CC doesn't go through.

The first time this happened, I was on Lux trying to Q (Light Bind) a Poppy. I thought it hit, but there was no effect. The Poppy had no items that would allow her to ignore CC (no Banshee's). However, I was on Lux and figured that I just missed a skill shot. Because Lux.

The second time this happened, I was on Annie with a stun charged. I cast my Q on Poppy, again, right as she was casting Steadfast Presence, and there was again no effect.

Both times, the Poppy cast her E (Heroic Charge) immediately as my projectile was in the air. The CC appeared to hit Poppy in her hitbox while she was dashing towards me. At the end of the dash, she was not CC'd.

Has anyone else experienced this bug?