But the change to shield has not been reverted. The boss does not have a shield during the 'up' phase. Only its health was reverted (decreased).
The reverted changes are (from the patch notes):
Reverted the Pinnacle Factotum's maximum health back to what it was before the previous patch; it will now match what was in patch v3.0.8.
Reverted the change to Shockwave so the stun can once again be blocked.