Hi there,Mine Sweet Amnesia Haze has the same symptoms like yours.Brown or black spots on leaves and some tips burn (excess of nutrient, but I prefer that tips burn.It means they have enough food.)Start showing at one to two weeks after flowering.Start from here and there on fan leaves.Then Spreading to top leaves.I think it’s normal to show symptoms like that in the late flowering stage.Plant is focusing on developing buds.So I just focus on my buds pests, mold or rot.BTW you can also check on other Amnesia diaries (
@BudGood have the same symptoms like us).Happy growing... ✌️