I`m just seconding the `give`m`more feed post from Bill here, GF.... it looks to me like the plant is even starting to scavenge some bottom leaves for nitrogen as I see some yellowing down low in one pic. Of course, the new growth is showing a different colouration also which is to some extent normal though more normal in the beginning weeks of flower. They look hungry. If you`re feeding 50% maybe go up next feed to 65-75% targeting 100 but not just doubling nutes in one fell swoop. Acclimatize them to change if been feeding this amount for a while, and they`ll take to more nutes better and likely accept a higher max dose if you take a step or two to get there. Burnt tips are merely a sign of a grower trying to max out their plants, I have a lot of respect for those growers.
Scavenging other journals with the same cultivar looking for whether there were specific nutrient issues or the actions taken around nute levels can really be the piece that gives you what you need to take things to the next level as a gardener. Don't be afraid to contact people either, who grew your cultivar and grill them with questions.
Hope its alright my piping up in here, and, understand that my experience comes from a lot of gardening generally, and a lot of prohibition outdoor bud, but my indoor `craft bud` game is my weakest,
so we`re learning together.