AirPods making high pitch noise (only left one)

Hello! I have the second generation AirPods without the wireless charging case. The left AirPod started making a high pitch noise recently. I can even hear it when it is inside the case and i put the AirPod near my ear. It is not really loud and I do not notice it when listening to music. Still, there is something off with the left Airpod. It just makes the noise and I can hear it at anytime. It does not matter if I am playing music on them, the left one makes the noise at any given time.