Anivia stun bug

So I actually found that if you play Anivia with the Hextech Protobelt-01 , there is a bug that happen when you dash (with the Protobelt) and cast your Q (Flash Frost) at the same time. At first, I thought the stun was invisible but I tested it a bit and no damage is dealt to monsters in front of me when doing it so I guess the stun just don't cast. Although, you can still activate your Q again (there is the little aura around it to show you the spell is in the air and can be poped by pressing Q again) but when you do, nothing happen except you get the cooldown.