Nitrogen deficiency would be (dark) green new leaves with pale or yellowing older leaves.

So, no, not nitrogen deficiency.

The pale leaf edges suggest a root problem. Perhaps due to unfavorable pH, perhaps to something else.

It is planted on either side of emerald cedars. There is also hostas, potential, hydrangea, and cotoneaster around the azalea and nothing else is having problems. Perhaps tomorrow I can do some exploratory digging to see if anything is bothering the roots.

Azaleas do better with more acid soil than all the others you named.

What's your prevailing sol pH?

Yes, symptoms look more like iron chlorosis than anything else and that is a direct effect from soil that is insufficiently acidic.

I have added iron chelate to the soil and top dressed with sheep manure.