wilted leaves on bush beans

I just noticed this today. I have small vigorous plants, but on a couple of the plants a leaf, or part of a leaf in some cases, is very wilted. Not wilted like a plant that needs watering (which it doesn't) but wilted like something that's pulled out of the ground and dead. Here is a pic of one of the leaves that is partially wilted.

here is another shot. They are in raised beds, the soil is moist but not overly so, it rained the other day. I don't see any insects.

Could it be sun burn? Or wind damage?

Our weather has been pretty good so far. The wilted parts of the leaf are so thin they stick like saran wrap to whatever they touch.

I guess I'll keep an eye on them. I didn't have this problem with my blue lake pole beans.

That looks like either heat stress or lack of water. Dig a foot down in your bed to see if there is a dry layer. Sometimes the water doesn't perculate all the way down or drains too fast.

If it's really dry, I found you must water THREE times. Once some in the evening, again in the early morning, heavier, and then a third time in the late morning real deep.

Just runs off if you try to water once, dig and look.

Could also be a critter burrowing under and ate the roots.