Japanese maple leaves browning and spotting

[Sbattey]

Hello!

The edges of the leaves on my Japanese maple are dying, and the leaves are starting to fall off. (Not a lot, just a few)

The tree was planted 1 week ago. It is a full moon maple. The tree has been watered twice now, and it has rained a few days.

It went through two hot days (about 70-75 F) and experienced a hail storm (small Washington hail, not enough to hurt it..probably)

I'm wondering what may be happening here. Is it disease? Could it be something in the soil? Is there another tree I can plant here that will be of similar size and character but more hardy?

Thank you for the help.

https://imgur.com/a/EdDBR