I've been growing this plant for almost 2 years, sharing cuttings with friends, etc.
It's bloomed continuously.
Today, I noticed that one of the older leaves was covered with a white fuzz:
So I got out my digital microscope and got some mediocre closeups of the fungal hyphae:
This seems to be something called botrytis or "gray mold" which can happen when cold/damp/and damaged plant tissue are present, as sometimes in our strawberries. Here's the life cycle (Development of Botrytis
gray mold diseases by George Agrios, Plant Pathology