Xoris Heavy Attack explosion counted towards Burston Prime Incarnon Evolution 3 challenge

[FoxfisherT10]

Was just leveling it in Elite Sanctuary Onslaught after putting a Forma on my Xoris and decided to get some kills for the challenge since I had just gotten my Burston Prime Incarnon. After using up my Incarnon's ammo, I checked how much affinity my Xoris had and it was only level 15. I decided to try and get some kills with it and when I detonated the thrown Xoris, it counted kills towards the Burston Prime's Incarnon challenge. It was really weird.