Berlin Now the Japanese manufacturer, who also describes incorrect inputs or incorrect reactions of its Joycon controllers as responsiveness syndrome, has come to terms. Nintendo promises Switch owners with defective joycons free repairs, even beyond the warranty period.
But before that, you should make sure that the problems cannot be solved by calibrating the affected joycon. Detailed instructions can be found on Nintendo’s help pages. If this does not remedy the situation, the free repair can be registered online.