While in an expediton with Untainteds active, The Sanibel's chosen Untainted is able to cancel the Player Character 's Aspect of Apocalypse - Infinity form, by while using it's Charge & Impale ability on the Player Character.
This renders the Player Character vulnerable to damage, even while using the Aspect of Apocalypse active.

While in an expediton with Untainteds active, The Sanibel's chosen Untainted can only be hit by 1 of the 10 hits from the Player Character's Gunglisnger's Brand - (Active Skill modifiers on the ability -> Leave no witness + Wild Gunsman). Most likely, The Sanibel's chosen Untainted hitbox is bugged, at least for this ability.