Leaf problema mid flower

Not how a nitrogen problem progresses. Leaves don't look excessively dark nor glosse, either. Bet your pH is too low. Looks most like a molybendium symptom, but it really doesn't 100% match any particular symptom on the leaf chart i have. leaf tip and margin burn relate to S-tox, k-def-and-tox and p-tox. But, this doesn't really look like any of those as far as progression i've witnessed. also, assess watering habits. If you don't have a wet-dry cycle, could be a rootzone issue. whehter you are soil or solless impacats bast practices in that regard. some simple things -- if you choose a volume of water to give as opposed to useing as much as required to do ti right, you likely water poorly. Keep it simple. Always water entire thing no matter what volume of water it requires and wait for it to lose a significant amount of weight before re-irrigating. Doing this early can allow you to increase fertigation later and take advantage of a more robust root mass. Still need some minimum dryback before you re-irrigate to avoid nasty random microbial growth and other rootzone issues.