No thrip damage to be seen so it's not thrips or any bug really. I got thrips so see the damage every day. Will be spraying soon tho there's only a couple here and there. Thrips leave shiny trails/patches on the leaves and if really bad it can look like windows in the leaves. The adults are easy to see with just my prescription reading glasses on but the babies need a 5X amgnifier that has the little 8X built in. $12 at most drug stores and lets you scan leaves really quick.
Might be a little Ca issue going on but that's debatable too. New growth looks robust and healthy.
What is your setup.? Water, nutes, pH and ppm kind of info.