But, my first thoughts were that you were under-watering.
I considered that as well but I have found that it is almost impossible to permanently damage succulents by under-watering, they always seem to respond favorably when watered well after a drought. Most people also have a tendency to over-water so that seemed more likely to be the case.
Very interesting, do you ever use Akadama for you indoor plants Norm?
I have never gone to the trouble/expense to investigate imported (Akadama/Kanuma) bonsai soils, preferring to stick with domestic substitutes. When I first moved toward proper bonsai mediums I discovered Turface which is a high fired clay product but I could not locate a local source for it. More recently I have been using Haydite which is derived from shale. I also like lava rock in appropriates sizes. Most of my plants also have some (the amount varies) Pine bark as the organic component.
If you have some of your bonsai mix on hand the next time you are re-potting (succulents in particular) I think you will be pleasantly surprised. That is all I use for Jades, Portulacaria, Aloe and Sansevieria. I was given a small piece of Spider Plant this summer and it has done very well in this type of medium. The only downside I can think of is the more frequent attention that will be required with this type of medium. With succulents though this is not really that big of an issue.