This same thing started to happen to me. When I am playing Onward, the left joy stick is movement. I will hold the joy stick to one side to move, if I release it, it physically goes to the center, but my avatar will drift to the right (keep moving). I can wiggle the stick to stop the movement, but sometimes it starts drifting again. It is a real problem in game because I can not stop.
I have removed the battery and let it sit, I will try that again.
What is next?
I went into Alt VR and it does not see to happen there, only did a real quick test.
I had this issue while under warranty and after exhaustive questioning and providing videos, they replaced my controller with a refurb...6 months later, same issue. I think it is a design flaw that if you play games that require using the thumb stick a lot , it just can't handle the usage. Looking online for a replacement and of course it isn't available (hint hint buy Quest 2) unless you go to ebay and then it's $100+ for a used controller.