I agree that its not a full on ‘end of the world’ case of root rot, but I disagree about organic based nutes staining roots.
If that were the case, then everyone growing in soil would have brown roots - and they dont. When I was using FoxFarm soil and nutes with organics in them - Mega Crop - I had pure white roots. When I changed to hydro - still using Mega Crop - I had pure white roots - except when they were sick. Ive seen plenty of pics of people growing in organic soil with organic teas and still have pure white roots.
I stick to the diagnosis thats its bacterial growth or some other health issue that makes them turn brown.
Edit: sorry bro. I think Im in what my wife calls my a$$hole-know-it-all-nit-picky mode and that may have come across the wrong way. Not wanting to start an argument. There are at least 10 different opinions on what is “best” for every aspect of growing our plants. If it works for you, then its good 