My mango pawpaw is doing the same thing, but only on the older leaves. The susquehanna 10 feet away is doing fine. Both are in full sun.

They still could be a little young.Possibly sunburn. Brady

With regards to my two, wouldn't both show symptoms if the issue was too much sun? They are the same age.

I would not entirely discount the idea of sun stress. My pawpaws did this too when they were younger (no holes in the leaves or ground though). One variety may be more susceptible to sun damage than the other. I had mine in pots and was able to bring them under the porch so they got only early morning direct sun. They just really took off when I moved them. One of mine did show more signs of stess than the other. I have NC-1 and Pennsylvania Golden.

It may be that a little shade will help the tree fight off what ever else is stressing it?

I've heard of planting sunflowers as temporary shade for young pawpaws, and just thought of adding an annual climber - perhaps a half-runner bean?

Has anyone tried this?

I wonder about something upright like sunflowers, particularly if they wouldn't compete too directly with the pawpaw, but I like the idea of an annual or other temporary shade crop/plant. Thanks for the idea.

We have dry summers, and I often got sun stress on my pawpaws, as they often grow in summer rain areas. I think your paw paws look fine.
John S
PDX OR