Eastern,
Two things occur to me that I have done. One is that you can put it in a heat box on low heat and see if the bamboo may not be dry enough. I know that tiller often changes on BBO's that I have built, and I have built about twenty of them. Th other thing that works great is to shave the belly down and glue a thin laminate on the belly where it is weak. One of the best bows I have I treated that way, and it is a great performer. 186 fps with a 500 grain arrow. You can either glue a lam just on the weak spot or shave down on both ends and put the thin lams on and re-tiller.
Dirty Dan