Autumn olive help

I have a bunch of autumn olives on the property. Most are doing fine even with pocket gopher harassment. I was looking at one of them today and it looks like it is either drought stressed or in need of nitrogen. I thought how could this be? I just watered them recently and they fix their own nitrogen. Any insights?

I'm not a whole lot of help here, maybe I can bump this to attract wiser people than me to help. I'm still learning what kills trees. At my place, it's deer or fungus, mostly.

Wow nice picture! From that it looks like a magnesium deficiency. Interesting

I swiped it off another thread here on Permies :)
I have used epsom salts for Mg deficiency before, not sure if that's best, more research would be appropriate...

I see a lot of threads here on minerals, too sick to dig through them today, might be worth reading a bunch of them.
Also WELL worth reading Bryant Redhawk's soil series:: Soil articles I think I recall him discussing Mg in there somewhere. Probably several somewheres.

It's the lacking of some nutrients (not azote, since this plant takes it from air) and, may be, high temperature....