I experienced something last night in Chummer that I am uncertain is a bug or a misunderstanding of the rules on my part, so...here we are.
I have a PhysAd with Magic 6/6, 1 Power Point from Initiation, 2 levels of Light Body free from my Mentor Spirit (Cat) and 2 levels of Adrenaline Rush from a Rating 2 Qi focus.
I added some bioware to the character. This lowered his Magic Rating from 6/6 to 5/6. However, it did not deactivate any given Ability. My understanding is that when I lose the Magic Point due to Essence Loss, I should also lose that many Abilities, as well.