Cymbidium new growth black spots

[irrka]

I got a cymbidium that outgrew its pot from Costco years ago and ended up dividing it to manageable sizes. I ended up losing a bunch of bulbs and haven’t been able to re-flower it since the division and now I’m having an additional issue of the new growth on one of the divisions coming up spotty. They are getting tap plus MSU vs just tap and intermittent mag supplementation. Roots look pretty good and juicy. Any ideas?

Last picture has oldest growth on the right and two newer ones on the left 🥺
Also I apologize for sideways pictures, they looked upright when I uploaded them and I don’t know how to fix that