Hey dude, whassup?
Yeah, nutes and soil. I think it depends how much nutes were in the soil to start with. When I did my outdoor garden the soil had enough nutes that my landscaper (who's into organics) said I wouldn't need any the first season!
Those leaves look so weird for N def though. Usually the leaf turns completely yellow then may brown. Not all follow that pattern and N deficiency does hit the lower leaves first so I'm not excluding it. It also follows what you are saying.
If it is N def, they are right, the color will come back. I have treated a N def with foliar feeds + root application and never seen it come back in hours, but you can expect to see a result in 1-3 days. The color will go green from the center on outwards and you'll see a dramatic uptick in growth rate.
I'd say Pot takes more nute than my other houseplants only because I am going for volume and quality but I've never used more than 1/2 str even at maximum. I am using the same nutes/str for my clones I'm doing soilless.