My Starlight Blue one started drifting upwards when I was playing FFVII Rebirth, less than a year after I bought it. I've found that spraying a bit of electrical contact cleaner around the stick, rotating it and leaving it to dry fixes it, but only temporarily. It always starts doing it again after a few days of use.
My original white one has a different issue with a creaky L2, I think I only used it for a week or two before it became too annoying. It happens intermittently, so I'm not sure they'd find anything wrong even if I tried to get a replacement. The blue controller has started having the same issue too, but with R2 and less frequently.