You’re plant needs fresh air coming in and out of that tent ph foliar spray and turn on the fans with some outside air coming maintain cool conditions with good ventilation and let you’re soil dry completely all the way before you water again
Could be heat or low humidity. Also, I don't see any other symptoms. If you've been a feeding steadily, can always give 1 extra irrigation of water-only between feeds and won't slow you down too much if not related.