Do yo rotate your plants? if you have the space and light for it, i would do it. Also good for the plants they not used to get light just from up above and 1 angle. Could be the position too. I have one plant close to my dehumidifier in and outtake, she has same signs. So heatswings in my case.
She could be needing less, by the looks of the size. Does she have different runoff? Could be if you feed her the same.
So check runoff(ph and ec), heat, light, airflow.