Denbrodium Red Emporer Problem
 

My denbrodiums are summering on my Northwest Florida, East facing back porch this summer, morning sun through trees. This is the first year I have had them outside, so I have never really had a pest or disease problem. Does anyone know what is happening to this leaf and what I can do about it?

Sunburn on the leaf. A little more shade while it gets better acclimated. Or your shade, or sun, whichever you prefer, has shifted some over the past couple months and it's now getting more intense sun that it wants.