After 2 layers of paste, and 3 layers of color, this morning I floated one of my lunar calendar prints in water to dissolve the rice paste. After swishing it a bit, I could see that the top 2 layers of color were washing away, leaving only the first blue that I applied.
My hunch is that I washed it out too quickly, and since the first blue was applied about 3 days ago, the soy on that layer had sufficient (just barely?) time to cure. Time is a variable for katazome on fabric -- you must allow the soymilk to cure/oxidize for several days at the very least, locking the colors into the fibers. I think this must be true for paper as well.
Here's the difference between the washed print and one still curing in peace and quiet.
Tonight I will add a final "glaze" of soymilk on the remaining prints, adding a bit more Payne's gray while I'm at it (this color looks most like indigo to me) and then allow the prints to cure for 3 or 4 days before washing them out. I saved my gelatin plate anticipating I might need it again!