Look good to me, although they may be a little dark from too much N? Not sure. It's hard to tell for me since I'm new too!

Ok, Looking through a list of nute problems with pics provided, along with the pics of the very tips of the leaves going yellow.... P, magnesium, zinc are my possible ideas. The VERY start of one of those. Don't really know, but it's something to check.

All looks good otherwise - LOVE those large buds!