The nute burn i am familiar with normally starts on the outter edges and works it wayin.

I am sure there are others i am not familiar with cuz i dont over nute anymore.

I say give it a couple more days to see if the plant is just processing and producing chlorophyll a bit slow on those leaves.

Though i still dont see the reason for alarm....

but of course maybe cuz thats i am using a monochrome computer sreen...hehehhehehhe