Not sure but my gut tells me the cracks are not right. As for the PVC for the handrail anchors....is that what you're saying? My rails sit in galvanized steel anchors. There are several pool builders as regulars on this forum and I'm sure they will kick in. For now...express your concerns about the issues, forcefully, and hold off on the final payment. Once you fork over the $$$ you may never see the PB again.
Al