Soybean WW bread question

I have been baking WW breads from Laurel's Kitchen Bread Book with great results - until I tried the soybean bread last weekend. It just won't rise as high as the others. Since soybean paste tightens the gluten, the instruction was to first knead the dough and rise once without the paste, then punch down and add the warm soybean pulp, knead well, rise again. Shape and proof and bake as normal after that. I tried 3 times, the first time, the dough felt limp after kneading in the soybean, and it did come up too high during proofing, sunk in the oven. I thought I had overkneaded the dough (in my KA, kneaded for 5 minutes without the soybean, then 5minutes after adding it). The 2nd time, I kneaded less after the soybean addition, still sunk in the oven. The 3rd time, I went to the other extreme and kneaded VERY WELL: 8 minutes without the soybean (for her other recipes it takes my KA about 10 minutes to fully knead, passing windowpane), then another 8 after the first rise and kneading in the soybean. I even hand kneaded a bit just to feel the dough is elastic enough. This time it didn't sink in the oven, mostly because I shortened the proofing time I suspect, it looks like this:

A far cry from the tall and light yogurt bread:

and the featherpuff bread:

So, what's the deal? Is this bread just not meant to be as tall? Am I not kneading enough? Too much? I am stumped.