I seem to remember this being a common issue around launch. If I remember correctly, Nintendo went so far as to replace some people’s joy cons if they couldn’t solve the issue. I’m surprised to hear that they’re not making that offer to you. How long have you had your console? Is the issue specific to any certain game?
I've had it since March but it only just started happening last month since I am a very infrequent gamer. No specific game. It's happened with Kart and Zelda many times.