Gamecube controller on Nintendo Switch not responding correctly?

I bought an adapter so that I can use my original Gamecube controller on the Nintendo Switch. On the whole, it works.

However, I have e.g. The problem with Smash Ultimate is that the button I put the normal attack on doesn't always work. So I tried different options. Whenever I launch the normal attack on e.g. "A" put the button does not respond in combat. No matter which one I replace it with (I've tried "L" "R" and "X"). The key on which the standard attack is located does not respond. In the Smash Ultimate menu, however, everything works as normal. All buttons go there.

With Mario Kart 8 Deluxe e.g. The problem is that my driver accelerates on his own. Means that I have a false start in every race, so reversing and braking is not possible. In the menu of the game, the A button goes again… It's really funny.

Don't think it's the controller. It works without any problems with the Gamecube…

Does anyone know the problem or has a good idea why?

Have you already switched the device off and on again?

Yes. I've already tried. Unfortunately didn't change anything…

And now?

And now I hope that someone has had a similar problem and can help me… Otherwise I will send the adapter back.

I would also show the pigs!

Just send something broken, I think it HACKS!