zed, death mark, and sheilds

If you are shielded while death mark is on you it still deals damage as if you were never shielded. While this may not seem like a big deal the damage that the mark does is very misleading. The mark is not affected by armor at all and it actually ignores all armor because it is just doing a % of the damage already done. It is super annoying when zed shadows away after dealing around 50% of your health and you then die because the mark did an insane amount of damage that you didn't know it was going to do. I've seen zeds mark do around 1200 damage multiple times. This would mean zed would have to do about 2600 damage in less than 2 seconds for a max rank mark to deal that much damage. I don't think there is a champion other than zed that can do this much damage so fast and I seriously think that there is a major glitch with his ult that is unnoted because you don't have time to realize what is truly going on because your dead in 2 seconds.