You say you "understand heat and bow stress when strung but these delaminations were unreasonable." You don't say whether these bows were left strung in your hot car. If so, the delams are "reasonable". Like Jeff says, heat is the issue. Even if you left them in the car unstrung, then strung and shot them before they cooled off, the problem is the heat, not the bows. Like Jeff, I'm a little confused by your reference to composite bows. If your bows had "glass" in them, they were composite bows in my opinion/definition of composite.