Leaves curling up on the edges (never seen that before)

Most of these comments are completly BS… Looks like to much light, they cure inwards to protect themselfe & lower transpiration rate… Everything else based on the fotos is completly BS! Dimm your lights a Little bit & it will stop ( common issue in vegetative state, in flowering they can handle excess ammounts of light better )

N excess causes K lockout (100% if the edgeis of bottom leaves are rusty burned and the tips also burnig)

Twisted new growth too... which could be related to trace elements but highly unlikley that is the cause. that stuff comes in any reputable soil or hydro nute line. Possibly too much light if it is isolated to highest leaves on plant. just because ec is 'right' doesn't mean it's fine. ratios of nutes is equally important. you can have a typically okay overall concentration but a poor ratio of available nutes and still run into both toxicities and deficiencies, fyi. EC is accurate enough for gardening, but the fact there are 3 or more conversion factors tells you how precise it is, lol... hardly.

Looking borderline over fed, but the leaf curling can be an early sign of a developing magnesium deficiency.

Root bound or too mutch light but its all good overall