Is there any noticeable free play in the wheel/QR when the servo switched off?
If so, remove your wheel from the base and check that all of the bolts holding both sides of the QR are still as tight as they were when you fitted them.
You could also check the two adjustable screws that keep the QR securing pin in place.
Check all of the servo mounting bracket bolts too.
Something could have worked it’s way a little loose if the noise from the servo has increased and you haven’t changed any settings.