Up her potassium dose and see how they do ... its definitely NOT cal mag issues you would have rust spots tiny ones on your leaves and you don't x nut defo look into more potassium 💚 Happy growing x
Oh, I thought it might be too much but it seemed strange to me that there are no symptoms on the whole plant and I haven't over-fertilized either, in fact, I fertilize them less. I'm going to increase the dose and see how it responds, thanks!!
From the burnt tips, it looks like excess of some nutrient; if you haven't overdone it, it seems like a calcium deficiency... There are comparison charts that are pretty clear (check the chart of your fertilizers, and it might help you).