How much water is it getting?

If you're looking for a quantity, I'll have to do the math, but it's a new planting with new drip irrigation. It's in a cluster of 4 plants all on the same line. They are flanked by .6gmp inline drip with 12" emitter spacing. The system is running for 20 minutes 3x a week in a shaded area. The soil is moist, but not wet. I believe it may be getting a bit more water than it wants. It has recently started putting out new leaves at the nodes where old leaves are getting ready to fall off.

How long ago did you plant it? If recently, likely the root ball is dry.

Have you checked if the emitter is emitting?

while you're looking for the cause of the wilt, rig temporary shade to provide a tad of help/relief.

I was going to say root rot too. I lost two Carpenterias to standing water this year. We had a downpour and they were in a low spot in my otherwise pretty sandy yard. They succumbed rapidly.

I lost one from being fried in too much sun! Our most successful two carpenterias are in a raised garden bed, north side of house so getting partial shade. I give them about a gallon of water maybe every 10-14 days during summer or dry spells.

Definitely root rot. Applying water on a hot day is a very bad thing for most native plants. Only water when it is cool.

When one out of multiple fail I always tell clients each plant has a personality and one might have gone into shock while others live. It could be handling or just the plant. If it has green leaves coming back out it means it still is alive and may make it. Best of luck to the plant :)