I'm a NB and even I think this can't be right. 600 damage siphoned every second for 4 seconds regained as health when before the patch it was around 150 max?
This was on the PTS the whole time and was even mentioned on forums, nothing was done. Now it's been allowed in live. This needs to be commented on by the dev team immediately.
The change couldn't be intentional, in my opinion, but if it is, we need to know about it. If it's unintentional, or a bug, or whatever, fix it, and put it in the known issues.
Come on ZoS... I'm really trying to love you, but you make it so difficult with stuff like this.