This sort of thing tends to happen on design-build projects, unless the specifications are very tight on the subject of geotechnical investigation. Common practice in CA is for Geotech to drill the site, then give the results to Design, who includes them in the bid package so ALL bidders get the same information. This maintains a standard level of investigative confidence in all bridge work (unless a rogue inspector gets in like happened with Bay Bridge foundation), regardless of the geology. This works well even in CA, which has the most varied geology of any state in the USA. If ODOT had utilized the same or similar practice, this likely would not have happened. Too often states will equate a robust in-house engineering staff with inflated government, and try to get by "on the cheap" with consultant engineering. The big pitfall here is you seldom have a private firm with a sufficiently extensive geotech knowledge base, unless your geology is very simple, uniform and stable.