What’s causing my leafs to curl?

If potassium is low, leaf edges can curl up from a lack of nutrient(K) to support guard cells that regulate stomata. Whenever the edges of the margin go up, it indicates a lack of "water" or a burning off of water, "cooling" faster than "uptake is occurring". But very small differences, the edges of the margin being affected, tell us the plant is dictating what parts of the leaf to sacrifice, telling us its a mobile nutrient at its root , (K). Potassium is the key nutrient responsible for regulating the turgor pressure within guard cells, which in turn controls the opening and closing of the stomata (pores) in plants. 90% of all water use during the day is cooling-related. More light = more cooling = more water movement = more osmosis = more pressure More airflow = more transpiration = more pressure. 2 plants closer to higher levels of airflow will have higher levels of transpiration, causing a higher pressure. Symptom overall of the plant not on old growth means it's not a true deficiency but potentially a very early symptom of antagonism of K via calmag over fert. The plant is photosynthesizing slightly faster than it can get water where it needs to be, therefore sacrificing the "edges" ever so slightly, not necessarily just the light; water movement is done with pressure, and the turgor pressure comes from various sources like airflow, not just light. Basically, the plant's pressure balance is off; she is pushing out ever so slightly more than she is taking up, whether that is a water issue below or above or a very early loss of guard cell function due to an antagonism of K, I'm not sure. It could just be basic environmentals, but I'm assuming you covered the basics. Best of luck. She looks well cared for, well done.