Sugar leaf death

What kind of lights are you using? What is the wattage of the light and what is the distance the light is from the actual plant itself. I had a 600 watt LED fecida light at 18 inchesnand it started butning the tips of my leaves first. It looked exactly like your pictures to be real with you. All i had to do to fix it though was move the light from 18 to 22 inches.

At second glance, their life cycle might also just be over... I don't see any white hairs, they're probably ready for harvest...

Usually calmag but it also happens if you flush. Most likely cause after that is too much N during flower. Only you, the grower, will know what's most likely of these, but I hope this is enough to solve your issue!

Look more of a potassium deficiency, With a marijuana potassium deficiency, you’ll generally see symptoms on older leaves, but not always. Sometimes you’ll see the symptoms at the top of the plant. Leaves with a potassium deficiency get yellow, brown, or burnt edges and tips. The burnt edges may look a little like nutrient burn, except the affected leaves also start turning yellow in the margins. check your ph make sure you are not locking out any nutrients.

Hey Growmie, After looking at everything it seems as if you're overfeeding your plant way too many nutrients for the stage of life she's in. It looks like she's basically done, so at this point, she should only be getting ph balanced water basically flushing her. Hopefully, I answered your question and remember "Happy Growing" and "Free your mind one puff at a time"

Looks like nute burn to me. Are you meassuring the EC/PPM of what you are feeding? Try giving it plain water and stop all feeding.