Root Abyss Boss Mechanics

Skill Books drop more frequently, I had 3-5 per boss yesterday. Did anyone else's Vellum not use his Poison Plasma attack? I waited a minute or two for it below 25% then 10% HP, it never came.

I wanted to add this in some time ago but kept forgetting, does anyone not a mage experience OHKO's from Pierre when using his Umbrella Thrust when using a movement skill into or out of its range? I survive perfectly fine if he pushes me back, but if I teleport into the skill or get caught as I'm teleporting (too slow) out of the range it turns into a OHKO.

Slightly unrelated, does anyone think the reason our Fafnir weapons and equips don't have the additional options (%Boss/PDR) is that we don't have Additional Options/Revamped Equip UI or did they actually remove them? Because these changes to boss drops and boss: drops feels copypasta, like MISS=>GUARD. Are the boss drops like this in KMS?

Vellum does still use poison. He used it in my run today.
I did not notice an increase in skill books... only got 1 between the 4 bosses.
Umbrella thrust does not OHKO my BM using DJ.

I believe Fiel mentioned there being tags for additional potential, but who knows how it would apply without the other requisite changes? I'd be very surprised if it worked properly.

I did not experience any of the hit box problems others described.