I have the iPhone 8 plus, 64GB, on Verizon. I received it Friday and have been having the intermittent earpiece issue since setup. I tried a hard reset multiple times. I have also tried toggling the speakerphone button when on a call (which works sometimes) but the issue always returns. I just chatted with Apple support. They had me walk through some troubleshooting steps. They asked if the device earpiece was clean of any debris and asked if I was using Wifi calling. I told them it was clean, and I was not using Wifi calling. They then had me take a voice memo and play it back. There was no static when I played back the voice memo. At this point they indicated because there was no static the earpiece was fine and that I should contact my carrier because it is likely their issue. So, the experience was not very helpful. I believe it is a software issue because it is intermittent and because it is happening across multiple carries. Hopefully enough people complain and they roll out an update.