Blackwater

yeah happens sometimes with young plants , nothing you can really do it's a root problem though if you want to tempt the devil you can try to break down the problem roots with a chelation agent like enzymes , humic acid, or beneficial bacteria including myco but it might make it worse before it gets better. Either they'll grow out of it or they wont and get stunted type of thing. Hope this helps growmie ! 🚀