Hey Blueraincoat It's a little hard to tell from the pics, but from what I can see an what you explained it sounds like it could be the start to a cal-mag deficiency. I would try adding a lil bit or do a foliar spray with some cal-mag. I don't know what brand your using so I dont want to say a certain rate of this to water so what ever your using for the cal-mag I personally would try doing a foliar feed make the plant work less thus more happy🙌 and once you have done that watch the new growth to make sure that has fixed the problem, Hopefully it will finger crossed. Also next time you water check your runoff pH just to make sure it is in a good range it seems like it is but I have had it happen to me where the water going in was a at a good pH but my runoff was way off and it started showing problems. So it's always good just to check. Good luck and Happy Growing! Hope this helps👍