I found this online about a “sport” of gold foliage on a mature green tree but I doubt that is what is happening to your plant.
My first recommendation is to call the nursery or visit the nursery. The plant is unusual in the nursery trade here, and I don’t have research from OSU about how to best grow it. Cistus may be able to tell you how other plants are growing this spring.
I found these photos from JC Raulson and their young potted trees look yellowish too. I hope you’ll let me know what the nursery tells you. Maybe this color is normal for trees this age.
This OSU article about environmental factors offers clues, but I don’t find an exact answer for you. Did you plant the tree with the root flare at the soil level? Is the drainage good or was soil waterlogged in winter?

Here's the advice I got from Preston at Cistus. Hopefully it will help anyone else researching this issue:

Hi Greg- It definitely looks like chlorosis, supplemental nitrogen is a good start, the fish fertilizer is fine but tends to be pretty weak in terms of actual nitrogen content so you may consider 2x or 3x the recommended dose or using a higher nitrogen fertilizer. I’d also recommend chelated iron such as ironite, this can be applied to the leaves and to the ground and usually works quickly. The wood chips are a good mulch but check that they are not too deep right up next to the trunk, pull them back away from the base of the trunk to let oxygen into the soil and keep it from staying overly wet. With recent warm weather and some iron these should start looking better. Good to see they came through the winter so well, it has been a very good tree in the Portland area.

Greg, thanks for getting back to us. I will leave this as shared to the public so it is available to all.