burnt tips on leaves during flowering

sometimes toxicitiies are a slow roll... it's the results of rate of use vs rate of intake... if it's only slightly off it can take several weeks to see that you are overfeeding ever so slightly.... when you dial back, you don't get an immediate response, either.. the damage is done and won't heal in this case. What is important is you canopy doesn't turn to died up crisp before it can properly finish ripening. So, if it stays minimize and preferably not pogressing, then that's all you can do... a little burn is no big deal. relative to the ratios and pH you are feeding you know you are pushing the boundaies... some ratio/concenrations may work better than others. If you've kept track of how you have fed... look back more than just a couple weeks and devise a slightly different plant next time... assuming your tmeps/rh and atmospheic co2 are consistent, you can expect you adjustments to work well. the more other variables change, the more difficult it is to adjust... the goal line will shift on you.

I get a little tip burn too. It’s not always from nutrients… can be too much or too little water— with infrequency. Heat, light, ph, etc. try a bloom tea for a a few days to give a flush and then go back at half strength nutes if you are really worried.

That's pretty typical of all grows I think.. and there's not much to be done and not much to worry about - Just ignore them unless the discoloration moves up the leaf... Good luck...