Maybe the soil is too wet and not draining well?

Another possible - weed killer? Maybe your neighbor was being careless when spraying weed killer? I know that 2,4-D will kill my shantung maple if sprayed on leaves.

I think the second set of leaves seem stressed. Fredricksburg has not seen much rain in the past few weeks ( Until this weekend). If you are not watering near the rootball then you will get the leaf symptoms you described. Get a moisture meter and insert it 6 inches from the base of the tree to a 4-6 inch depth. You can get them at Lowes or HD. That will be the best way to tell if your rootball is getting the water it needs.

Thanks for all of the responses. I think that the most likely is the lack of water as I have just added them to my irrigation.

I have found out from the nursery that the dark older leaves and light new leaves is normal in a vigorous plant. My concern is for the edge curling and browning.

We are getting rain now and the irrigation should help as well. I will see if things change.