Left AirPods Pro has crackling/vibration sound when Noise Control is enabled

Within the last coupe of weeks I have noticed that when I am talking to someone I hear a crackle or vibration sound when my voice hits a certain frequency. I can hum a tune and pitch it up and down to create the same crackling/vibration noise. I have found that this is only caused when Noise Control is enabled and either set to Cancellation or Transparency. If I turn off Noise Control the crackling/vibration sound goes away.

I've already reset them...with no luck.

Need help in understanding other options as the warranty just expired a few months ago and they are willing to do nothing about it.