You are able to select/ deselect cards by tapping them in the cards menu. When you have too many cards the game will automatically select a set for you, but you are still able to de select those cars by tapping them if you would rather a different combination
That is strange. This is the first we have heard of this.
If you are able to send us in a video of the issue happening that would be a great help. Or, if anyone else who has this issue comments on this topic with the same issue.