I'm betting that you have the beginnings of a Ca-Mag deficiency. Give them a shot of Epsom Salts for now, and go get some Cal-Mag
You definitely aint low in either P or K according to that test. It shows you lack N. With the levels of P & K you're showing, you want to add something with high N and little to no P or K. Fish emulsion (5-1-1) would do the trick, but it stinks all to hell. There are other choices that would work as well, I just cant think this early.
Also, not knowing your nutrient regimen, I would most definitely be feeding CalMag at least every other water. I use it every water.
I decimated my first two crops because of a cal deficiency. Looks for all the world to be nute burn. And it starts right at the second week of flower.
pH could be a factor, although all the votes aint quite in on how much it (pH) affects soil grows and organics. You wanna check your solution after you add nutes until you get to know the stuff you are using. My water is right at 7.6 to 7.8 out of the tap. I add my nutes and it gets to right at 6.8 to 7. Thanks to Tim McVeigh, most fertilizer companies now derive their Nitrogen from urea, and it's acidic so it lowers pH. You'll wanna be keeping an eye on the run-off water pH. That's what will tell you whats going on inside.
I cannot understate the importance of Cal-Mag. My first two grows were decimated at the same point, right at the second week of flower, when they first showed signs of "something" that looked a whole lot like a deficiency (or nute burn). Come to find out that's when they need a lot of Calcium and Magnesium. Epsom Salts would be good for the time being (1 Tbsp per Gal), but def get some cal-mag (I use the Botanicare, it's less expensive.
At 65 you aint got a problem. My room gets to 50 or so regularly. However cold(40 or below) COULD have been the problem. Cold will cause nutrients to lock out, just like high or low pH. (I just recently learned that!!!), and nitrogen seems to be one of the first to get locked out. I doubt this is the case here, as your test showed little to no N in the soil. In a lock out, the element would be there aplenty, just not in a form usable to the plant.
You could have any number of things going on, but I'm going with the CalMag deficiency.
Hope this helps.