Check closely for aphids. My red ripper peas had an aphid infestation and I almost missed it. Their leaves were looking just like that. Now that I'm getting the aphids under control, the leaves aren't blistery looking.

If aphids, look on the underside of leaves.

Could also be a weedkiller. Any chance of that?

No weed killer. Could be aphids but dont see any on the plants now.

Have you had cold weather? Sometimes when leaves are forming and the weather turns cool, the leaves will curl.

Is it spinach? Mine looks like that, wrinkled up>