CC Immunity not being given after a "Hard CC" effect wears off.

North_esp

https://www.youtube.com/watch?v=wXy7jkca9tY&feature=youtu.be

This is something I'm sure we all have experienced at one time or another. The dreaded double CC. Unless I am way off base, after a cc effect (in this case a knockdown) wears off, the player should receive the normal CC immunity that is given after breaking free. This happens a lot in pvp and pve as well. I happened to be recording, so I thought I would post here.

Mystrius_Archaion

This has been happening since Morrowind launched at least. I noticed this with the boss duo in Nchuleftingth, Friar Hadelar and Renduril the Hammer.
Those bosses make your character repeatedly "take a knee" like a normal stun, which breaks after 1 second, but they repeatedly do this over and over and over barely giving you any time to survive by using any skill. It makes this by far the hardest boss in any dungeon in the game which is only alleviated by the fact that they are in a public dungeon and thus have less health and lower damage than other bosses.
When I can easily solo every boss in every delve and public dungeon and even solo many normal mode dungeon boss but this one boss who should be easier gives me trouble, something just isn't right.