:smoking:... just that one spot AI, more or less? Up high like this, usually it's a micronute defc., but with so few/scattered symptoms, likely isn't and is just a touch of burn,... could be a bit of both since heavy P inputs can mess with micronute uptake/availability.... Aside from checking in-pot ph to mahc sure nothing is off there, easing up on the nutes for a bit is a start,... but get that pH checked, doesn't matter the nute type/brand, pH can drift off all too easily,...
Look into the Accurate 8 (3rd patient in a row I've said this too!) soil pH probe, or the identical unit under a different brand name.... Start with Amazon for bst pricing and choices, in EU Control Wizard products (original maker) isn't available, but other brands are, same unit, same Chinese factory!