Hey! Humidity is alright, 60% is good for veg. I'd say it's got to do with nutrients, given those brown, rusty tip spots I'd maybe the beginning of a calcium deficiency. A bit early to tell but keep an eye on that, if those brown spots keep spreading you'll to give more calcium. (remember when mixing your nutrients, CalMag always goes first, micro, then grow/bloom nutrients, last PH adjusters.) Hope this helped. Good luck and happy growing!