Bjork

Ruins of Lordaeron
Beyond King's Alley, choose the side encounters before finishing with Rath'mael. Approach the market statue from Lordamere Overlook for The Abandoned's wave event. Viktor the Vile is optional: the chimney in the house southwest of the overlook starts the waves that bring the boss out, so recover health and mana before touching it. Clear nearby groups before engaging Bjork's central patrol rather than combining the fights.
Bjork
Bjork tests patrol isolation and whether casters stop spending damage spells into Anti-Magic Shield.
Abilities

Anti-Magic Shield
Creates an anti-magic shell around you granting magic immunity for 3 seconds.
Anti-Magic Shield grants magic immunity for 3 seconds. Hold magic damage until it expires; physical attacks can continue.
Tank- Pull Bjork's patrol into cleared space before fighting it. Continue physical attacks during Anti-Magic Shield rather than relying on magic damage for threat.
Healer- Keep healing Bjork's target while Anti-Magic Shield pauses the casters' damage. The shield is not a break in the tank's incoming damage.
Damage- Wait out Anti-Magic Shield before committing magic damage. Physical attacks can continue while casters hold their damage spells.