If I have to venture a guess…..I’m betting your soil is running outta juice to sufficiently feed this lady. It’s the most common problem with living/organic soils in flower.
My reasoning: it’s too late in the game for high N to be rearing its ugly head, so I doubt a lock out….although if your ph is off that could do it…
And I’m assuming you’ve got your watering practices down, since you said you’ve grown before….