I'm guessing it fried, triggered dormant eyes to grow and the roots weren't enough to support the new eyes like before. I moved a couple of sporting divisions from shade to sun in the past that fried instantly, but with constant water new and more eyes grew.

Paul

I moved a very large clump of Paul's Glory last summer, too. Hate the way the leaves go parchment. Put it in lots of shade underneath a pine tree. Came back reduced by about half but at least it's not gone parchment yet.

I'm thinking it looks a little too deep.
If MB spring as anything like MN spring, the hostas taht were too deep sat in water, then froze and thawed and froze again, really rotting the crown.

Is the crown at ground level?

I decided to dig it up and see what was going on. It is planted in heavy soil and I couldn't brush it off to get a good look, so I hosed it off. The roots looked fine. I think it was too deep. I've replanted and I think the leaves look somewhat looser now. I hope it will rebound.