Thanks for the reply! That does sound like quite the pickle.
FYI, I happened to see on the Z-Wave Alliance website that Sengled has a recently certified (in August) Z-Wave bulb that supports S2, but it is not a color bulb (product manual) so that can explain why they aren’t running into a similiar issue. I couldn’t find it for sale anywhere so maybe it’s not released yet. Since it’s not color it wouldn’t meet my needs, anyway. Just passing the info along in case it is useful to know.