Canoeing / tacoing leaves!! :(

Hey guys I have been experiencing a small problem in the Grow room I have two plants that are 45 days into flowering from the switch and I’m experiencing tacoing leaves everything is pointing towards heat stress but they’ve been in the same environment for a while now and am wondering if there is a different problem going on and how worried i should be. The temps have been between 68-84 throughout the grow with around 40-60 humidity. I did run into a problems about two weeks ago with my 750 watt bulb blowing on me. Switched to a 400w until the new one came in and then saw this problem begin i feed with canna coco line of nutes and my ph is 5.7 and PPm around 600. Do you guys think they got used to my 400w for a week and then are chocked for the 750 back up and running? I currently have it dimmed at 60% as of last night. Other than the tacoing leaves everything looks and has been going for up until now. All input is welcomed. Thank you.

Also I should note that I have two much smaller plants in the same 4x4 that are uneffected.

It could be a light issue. Move your light up a bit or keep it dimmed for a few days. It could also be due to heat. Moving the light up or dimming it, will help you figure out if it is a heat or light issue within a few days or less

I agree to much light to close. The reason the small plants aren't affected is well because there shorter. Also the reason they weren't affected before when they were smaller.

Some strains just have that weird tendency.

Thanks for the input guys. I noticed even the bottom of the two plants are doing it as well. Coming up on my last two weeks. Would like to see them finish strong. Ill dim the lights down to 60%

find what the temp is at that problem plant, verify your temp measurement device is accurate