Getting champ upgrades from carasel

I had a bench filled with 3 cost champs rolling for a voli 3star and only had 1 missing. Got the last one from a carasel round. I had 3 completed items stacked on my voli at this point and it dropped the completed frc from my voli in favour of the component what was on the carasel one. I don’t know if it is the intended way for it to work but I feel like it shouldn’t be.