Yes I get this several times a day (10+ times). I've found that either going in and out of airplane mode, or more easily, attempting to place a call (doesn't matter if it connects, I usually just call my voicemail and hang up immediately) fixes it. I had this issue much less frequently with the GS4 and I had a previous GS5 that I turned in on warranty for an unrelated microphone issue which had the same problem. I live in a big city if that matters at all as it's possible it's a network issue (I often go into buildings/elevators where there is no service which sometimes seems to cause it when the phone tries to reconnect to the network).