Veigar's Event Horizon fails to stop dashes sometimes

Veigar's Event Horizon occasionally fails to stop dashes like Jarvan's Dragon Strike or Diana's Lunar Rush.

Steps to Reproduce

1. Enter game as Veigar with opposing team Jarvan or Diana.
2. Use Event Horizon to stop their dash.
3. Observe that the dash completes without being stopped occasionally.

Example Video https://www.youtube.com/watch?v=lOD5ahTe8No