I don't have the reference for this, but I recall the seals between shuttle booster segments were originally engineered to use asbestos, not rubber as the gaske

I don't have the reference for this, but I recall the seals between shuttle booster segments were originally engineered to use asbestos, not rubber as the gasket. The engineery qualities of asbestos for this purpose were perfectly understood, lower tempature lift-offs would not have been an issue, and most importantly, all the expensive live testing had already been performed when higher-ups recognized how politically incorrect asbestos was, even though a program as high-tech as the shuttle program was perfectly capable of handling asbestos perfectly safely. There probably was no $1M engineering fee that would have ever fixed this, because the multi-$M live fire tests were complete. No one considered this relatively minor engineering change (after all, the seal was redesigned to work with rubber) worthy of another round of very expensive tests (which primarily focused on the motor). In a similar fashion (sorry, also doing this from memory, no reference) sometime in the late 80s or early 90s the main fuel tank insulation was switched-out because foam manufactured with CFC became verboten, so another material, with apparently unknown (or not completely desireable) engineering characteristics, was swapped in. I never recall hearing about ice ripping off big chuncks of fuel tank foam during the boost phase in the 80s. I only remember hearing about this starting in the 90s (or at least after the Challenger accident). This is certainly tangential to the OP, except that there probably was copious high-priced consulting which provided political cover for both of these mistakes.