Discoloration 3 weeks into flowering

Your pH is just fine... there's no problem in that regard. The feed chart for your pH Connoisseur nutes says to give them 4ml/l throughout the grow and you're only giving 1.59... I would take those nutes up a notch to at least 2.5 or 3ml/l. As far as the damaged leaves are concerned, they're never going to repair themselves so don't expect that - what you SHOULD expect, if you can correct the problem, is that no new leaves will show the same discoloration... Good luck!

Hi there If your in coco im going to say Ph imbalance.. If in soil i would flush then add a PK booster, Best of luck 🌱

Looks like a ph imbalance. Try adjusting your ph up to 6.2