to NGA
I don't know, but perhaps someone here may have an idea or know.
I will say that I had something similar show up on a Medusa type Euphorbia. I could never really tell what it was or what might be causing it. The plant itself seemed to be healthy and continued with new grow. However, I didn't like it and suspected some sort of scale insect damage. A strong magnifying glass didn't help me prove that, but I decided to spray it with insecticidal soap. I ended up doing that spraying three times over a period of a couple of months. The reason I continued with the process was because after the first treatment, there was a lot peeling on the surface. Just an extremely thin surface peel like sunburned skin when when new skin replaces it. After the three treatments, it was back to looking healthy and unmarred again. It has remained clear now for four months prox., so I think that was probably an indication of insect damage. Maybe scale or maybe some other microscopic sized pest. It did not show up among other plants.
I'm not recommending you just jump in and spray. Wait and see if someone here has a better idea of the cause. But if no one comes up with something else, it's something you might keep in mind if it doesn't resolve without intervention.
