How To Fix Ps 4 Controller L 3 Button. Insert a needle or paperclip in the pinhole on the back of the controller. This will restore the default settings on your controller.
I hope you solve it, fortunately for me, my controller is a Scuf so joysticks remove easily without removing the rear casing.
By depressing the right stick you'll feel a satisfying click that indicates you've just pressed.
My controller was showing the exact same problem and I just bought a new one because I don't have the time to deal with it. Turns out it did end up being steam that was running in the background. You'll find a hole on the upper right.