Working on the incarnon for burston and I am on the third evolution. All of a sudden the incarnon is not showing on the gun, and progress for the next node "kill 100 enemies with incarnon form" is not progressing. I'll go into a mission, get the headshots and activate the incarnon form, but no kills i get will do anything and in the challenge tab it doesn't even show it as one.

Edit: So the issue resolved itself after I entered sanctuary onslaught. For some reason as soon as I entered a round of that, the challenge finally showed up and kills started counting, and the incarnon cosmetic appeared on the gun. Restarting, taking the gun on and off, changing evolutions, going solo, running other missions, none of those things worked. Just randomly going into sanctuary for an xp run resolved it somehow.