I hear most people say that the knockback is the aggro reduction in this fight. Is this correct? For me it seems that aggro is normal during this attack and its when he does his random intercept he wipes all aggro (similar to spider boss/anhilators).

I know most of you dont really care but for those that do, your input will be greatly appreciated.

Quick answer: no one cares :P.

Longer answer, afaik knockbacks in the game do *some* aggro reduction, I doubt Force Punch is an exception.

However the aggro "wipe" (if it even is a wipe, I don't remember since it's been a while since I've been in ZG), is likely from the charge.

It is a deaggro.