Plant leaves cupping up

Hey guys, I would like advice on this, yesterday my plant started to cup upwards a bit, I have 250w HPS 60cm up from top of plant, temps stable 28C humidity 55% didnt watered it for 3days, but last time I watered was with General Hydroponics Flora COCO series, gave her 1/4 strenght and cal-mag 1ml per 5l, I am not sure if its from heat or overfed/overwatered.

Looks fine to me

Could be a little heat stress... nothing to worry about. If new growth is healthy the "problem" is over.

got a small fan in there...?

Yes, I also suspect a little heatstress.

Sorry guys for late reply, thanks for all posts, Grow tent is Secret Jardin DS90, I have two fans one clip on that is blowing on plant and one tower vent that is blowing on wall of tent, 235cfm exhaust on top and about 175cfm intake , planing to buy 2 more a bit bigger clip on oscillation fans, Adjust A Wing Defener and pulled light closer 45cm from plant top , temps are 26C, max 27,7C around top of plant, 55-60%RH, dont mind the net was just trying to get it there, 16days old auto, Think Different
I was thinking about cool tube or hood but not sure if I really need it or would it help ?

Your temps are fine, and the two fans that you're using should provide good air circulation.

Thanks, I added two more photos of some younger leaves that are too kinda upwards on edges so Im really not sure if its heatstress, because she is growing normally, didnt saw any slowed growth