This is one of those “post it now, maybe remember it later” things:
I wear a corded, noise-reducing headphone set to listen to podcasts while I mow the yard. Today, I intermittently lost audio, but the podcast kept playing. I unplugged the phones, plugged them back in, and the audio would restart. I tried a a set of corded earbuds with the same result. As I was about to give up, I remembered that I had used a Bluetooth headset earlier in the morning when I walked the dog. When I looked at the Bluetooth settings, I saw that that headset was still connected. Then, I realized that the times that I lost connection were all when I had walked near the house. The phone was reconnecting to the Bluetooth headset whenever it got close enough. Turning off the Bluetooth headset fixed the problem.