My variegated rubber has the same problem. It came with some spots on it, I had it in a western window. After moving it to an eastern window, the spots grew and leaves are now becoming crisp. Do I remove the leaves or wait for the to drop. Or do I prune the tree altogether, cutting from below the bad leaves? Will it continue to grow? How do I safely prune, if that's the thing to do? As you can see, it is the uppermost leaves? Thank you for your help.
