I think there is a fair bit of us that probably know about the problems about the infinite stuns and staggers or have experienced this issue from not just npcs but also human players (intentional on their end or unknowingly they were doing it). I think plenty of us noticed how stuns and staggers and immobility pots and such were broken pretty badly after the release of morrowind chapter. But the principle of how others are infinitely stunning from experimentation to figure out how they are doing it is a bit odd. Simplest thing is using heavy attacks to weave right after someone is stunned or pinned or whatnot to remove the immunity that you are given after a stun and whatnot to re enable someone to be stunned or staggered and whatnot again... not even a second after doing it, when the heavy attack is completed you can do it again. Tested this with a fairly weak zerg in cyrodiil to find someone that was fairly tanky and we got him lifted up in the air enough where we stopped attacking him and let him fall to his death. Abilities like meteor and volcanic rune lifts people up in the air and stuff like clench resets the area where they are at as ground so you can weave just right with about 3 people or more to literally make someone airborne quite a distance, you do need more people because it is kind of hard to judge distance but after a certain distance you have to use meteor to lift them higher. There are certain abilities that break this chain however, stuff like the throwing javelin is a prime example of breaking this chain, as it literally throws them out of, as well as scatter shot too. You can do this same thing to npcs as well, even though most die pretty easily before you even get the chance to.