<30% RH is pretty dry but you only have a few more days. Are any of the leaves near the flowers "crispy" dry, other than the crispy tips that you had before? If you're worried bump it up to 35-40% and see if that helps.
Disclaimer: I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.