I heard later model switches doesn't have the problem much but early ones like the *Red/Blue and Gray* always starts getting that issue. Its always the left Joycon
-_- mine too, Have to get dust out the stick, if that doesn't work I might have to buy new stick or joy-con
Mine started on my right joy-con. ...Then it spread to the left. I just got some replacement analogue sticks. They are very cheap and easy to replace.
I have issues with the right stick on my red joycons and they disconnect The joycons are the worst controllers I ever used