Perhaps edema? High humidity, wet soil (or potting mix) and coolish temperatures?

That's a total guess without knowing where you live & how you're growing it. Indoors, outdoors or in a greenhouse? Pot or the ground? And more?

Hi jean,

Thanks for the initial info. I live in Hawaii and it's planted outdoors in the ground. Temperatures are normally pretty warm but humidity varies here.

Plants, indoors or out, even in Hawaii, can get edema, sometimes spelled oedema.

Ah ic, thanks. Do you have any suggestions on how to deal with it?