To be certain, I left the second rise for two hours, and observed that there was no further change. So obviously the yeast had died. With all respect to Elizabeth Harbison and her book full of good recipes, her post contains some mythology that should be corrected. I make salt-free bread in and out of bread machines. I also make sugar-free bread.
Moister bread rises faster.
If you put in sweeteners, it gives the yeast a jet-assist. This doesn't apply much to bread machines, which don't usually have programmable temperature settings. If your bread mushrooms and collapses, it' s rising too fast. Reduce yeast, sugar, or water. If the bread doesn't rise fast enough, add yeast, or add water.