One of my Xbox One controllers is being wonky,
randomly turns on and off, and thumbstick input going crazy (When connected via USB, when wireless it wont sync),

Then it failed a firmware update, MS wants $60 for a replacement, HA.

I can buy a new one for $20 from walmart using my store credit from their savings catcher thing,
and then just keep this one, take it apart and clean anything that looks dirty.

I'm thinkin' something is on the thumbstick circuit causing the controller to go crazy and shut itself off.
(Similar to how I had an issue with a roach shorting my XB360 Slim touch sensor chip)

Does it on both PC and Xbox One... connected Via USB.
2nd controller works fine.

Just wondered if anyone had any similar experience..

MS said it's full cost replacement... so I'd rather just buy a new one and possibly fix this one.

Controller wasnt dropped AFAIK.

I think it is just a faulty design. Mine started doing that recently as well. I keep it plugged in via usb cord to my PC but the left thumb stick started spiking very badly and then the whole controller would fritz out for a second or two. I took it apart and nothing looks wrong on the inside.