Leaves curling up on one plant. Anyone know what this is?

This fine female is Sleestack x Skunk she is at week 5 of flowering and I've been noticing her leaves pointing down for awhile except today I looked at it and one of the fan leaves is curling up right under the top leaves that are curling down. Weird Huh? Also the top cola isn't filling in at the very top. She gets watered about once every 3 to 5 days, so I know she's not under or over watered. She gets fed every other watering the same amount as the other two and they have no problems. She did have a N def last week but I got that cleared up by adding an extra 1/2 tsp of fertilizer to a gallon of water. It shouldn't be heat either as the Special Kush is taller and closer to the light with none of the same problems. I'm not overly worried about it as they all should be done in the next few weeks but if it's something I can fix I want to do it. I added some other pics to the mix so you guys can see the other two. The way they sit in the closet is from left to right Sleestack x Skunk, Fruit Spirit, and Special Kush #1.

Picture 1,2,3 & 4: The plants are undergoing heatstress so, raise your light. They are also reverting to vegatative state, check your timers\check for hermi glands\you may have overdone the nitrogen!!!!

I agree...the cupping is from heat stress..

No hermie glands and the timer is good. I didn't deviate much from my normal schedule to fix the N def, like I said I just added an extra 1/2 tsp of GBH to plain water. I moved the light up about 3 more inches, current temp is 73 degrees F with a RH of 39. What makes you think it's going back to veg? +rep to both of you for the quick responses.

looks to me like 2 things honestly, the clawed leaves look like theres a nitrogen deficiency, and the leaves starting to curl/fold in on themselves look like heat stress.

Move the light up and raise the shorter one with bricks os they are the same if you like.