I've noticed that after spraying or watering my S. brunonianum, they would form unusually large spheres of water in the center of the rosette. This may be connected to a slightly powdery growth on the leaves; whatever water landed on the plants would coalesce into these orbs, with some of the powder floating on the surface.
Sorry for the low res pictures.
Here is a cristate plant with a water orb:
Another brunonianum with a water orb. If you look closely , you can see some fungus gnat larvae that have become trapped in the sphere.
Has anyone else grown this plant and witnessed this odd trait?