Protea's Artillery won't add multiplier when hitting enemies caught by Vauban's vortex

[(NSW)Belaptir]

As title. I've noticed this after playing several games with someone using Vauban. Basically, when Protea's Artillery hit enemies that are caught within the Vortex, the artillery multiplier won't go up making the skill pointless to use in this situation. It happened in several modes, both railjack and planetary missions. It only happens with the vortex, Bastille is safe.