Bugsplat at champion selection

it has never happenned before, but a month ago, every time I get to the chammpion selection phase, the client closes and informs me that somthing broke, after that, the client immediately launches itslef back and still in the champ select, altough I can hear the sound of the timer and team messages, I cannot click and it it just keeps loading. in the end, I dodge, and I get the 30min queue ban.

I have tried a full repair, but it was of no help. If someone has an idea, please share.