Mission 75 for the part 3 Progression Mission's requirements are pretty simple. Fuse Relickeeper.

I have a relic keeper that I have obtained via fusion in my champion pool. However I am not gaining credit on this mission. 

I'm currently in the process of trying to fuse the new legendary unit, and the idea of having to completely stop fusing the new legendary (As it costs energy, and ascension pots) to swap over to Relickeeper, to fuse him a second time (Costing probably well over a thousand energy  many ascension potions) would not be desirable. 

I already have a Relic Keeper that was obtained by Fusion, why am I not getting credit for this mission?