Second video:
https://youtu.be/HZllkKHN0wk
Appears miti is not being penetrated when regen bonus is not in effect. Working as it should vs high regen.
Angelic, 2x Armored Companions, Stone Potion, and Earthfusion legs vs No miti at all
Identical regen bonuses (euphoric, regen, sacri)
Damage was similar.
When one person had more miti and neither player had regen bonuses (miti hammer and especially FDA), there was no penetration of miti.