This thing happened to me like 4-6 times already
My board was full **(6/6)** and my slots at the bottom too and let's say I have **2 Vayne.**
During the Carousel, I pick a **3rd Vayne** BUT it doesn't merge, so I try to move all the Vayne on the Board, I try to wait a round or two, or to put the 3 Vayne at the bottom slot, but **NOTHING is working** forcing you to sell it and then roll a new Vayne.
This is a huge bug imo especially when it is with legendary champs rly hard to roll.