Ann, thank you. I am mostly sure it is sun scorch as I just pulled up a mass of ragweed from around it exposing it to a VERY hot, dry day when it wasn't expecting it.
It has now been raining for two days so I'm hoping that will make it happier. These hostas keep surprising me when I find them under my wildflowers. I still haven't pinpointed where the previous owner planted them, but it was apparently everywhere. Here are two additional photos of it outdoors.