Crispy at the bottom suggests root problems to me (bound)... Because your pH seems fine (so long as there's some slight variation every feed). They're in small pots so could be a hunger issue too as they move deeper into flower and crave more PK.
Usually I'd say whenever any issue presents itself to flush and readjust the feed, but I don't think you are overfed... If anything they're hungry imo, but then your feed looks good, which is why I think it's a root thing!