Collectibles disappearing when removed from set

I had 34 cup chase collectibles in the set that requires 35 (gold choice player pack). I decided to remove them all to complete the set that requires 30 instead (gold crown pack), but when I added my collectibles to this last set, it says that I only have 20 of them and that 10 are still missing. Where did the last 14 go?

See video here https://www.youtube.com/watch?v=9A0zdm08oyo