Teleport not being cancelled on anivia

Any champ that I have played that gets stunned, knocked up, feared, silenced, pulled, rooted, or killed (even when the death procs a revive passive or ability like ziliean or GA) the teleport has been cancelled except when it comes to Anivia.

I think that her being able to start casting teleport right before being sent into her egg form and teleport not cancelling like it does with every other champ should be considered a bug. It not only gives her a passive that makes her harder to kill but gives her an almost zero risk way to escape any situation that does not have high enough damage to burst her down before teleport finishes casting.

If she is left being able to do this then any other champ with the same style of passive should be able to do that game thing.