Getting champions last second that don't combine

This is one of the most annoying things about TFT right now IMO... When you have 1s or less left on the clock and you are rerolling to try and get that one last champion you need for a 3 star or a 2 star legendary, and you get the card, but it doesn't combine before your match starts and they just sit on your bench.... I can't imagine that there is some sort of reason for this happening, the way I see it, this is a bug. If you buy a champion card before your match starts, and they can combine, they SHOULD combine before the match. I suggest either fixing this so that the champions always combine if you have them. Or if this is for some reason a intentional mechanic of the gamemode, make champion combining MANUAL so that if this happens, the only thing you can blame is yourself.