I decided to run a speed test while on a VoLTE call with AT&T. I know it was VoLTE because the LTE symbol remained during the call. Anyway, I used the Ookla Speedtest before, during and after the call to the same server. The results were as follows: Before ping 43 ms, 60.30 Mbps down, 21.42 Mbps up. During ping 59 ms, 36.66 Mbps down, 10.63 Mbps up. After ping 38 ms, 60.32 Mbps down, 16.12 Mbps up. As you can see during the call, the ping increased, download speeds dropped by about 40% and uploads drop by around half. If the phone didn't say LTE and the Speedtest didn't report LTE, I would think it dropped to HSPDA+. Is this normal?