iphone Xs distorted audio through ear piece but not speaker

I had this issue with my first iPhone Xs. It was replaced by Apple about a year ago. Now I having the same problem on the replacement phone.

As described in another thread:

iPhone Xs. Distorted sound (fuzzy) in earpiece on calls and FaceTime audio. Switching to speaker - not distorted. Switch back to earpiece, distorted. With Bose or Dre wireless bluetooth headphone attached - no distortion. Latest iOS installed. Phone restart has been done more than once. If turn Bluetooth off in settings - still distorted.

There is obviously an issue with the earpiece speaker. I wonder if this is a common problem? Is there a solution?