Device : samsung Galaxy s9 

OS : Android 8.0 Oreo Samsung Experience 9.0 ( I'm pretty sure...I hope)

WTR : 

Step 1) acquire several different sets of 5* or 6* artifacts (I tried using the same set and it didn't work)

Step 2) put these different 5* or 6* artifacts on a couple different champions (make sure you have completed all challenges prior to artifact challenge 9.6)

Step 3) when the artifacts are equipped, nothing happens. And yes, I had 3 different sets of 5* artifacts on three different champions.

Description:  does not show challenge has been completed once the artifacts are applied to the champions