Similar thing has happened to me. I joined a security team in a Big Bank. During the first month of my work I discovered a terrible and obvious security hole, w

Similar thing has happened to me. I joined a security team in a Big Bank. During the first month of my work I discovered a terrible and obvious security hole, which was there for years. My manager took me aside and explained that they can't fix it, or even start doing anything about it, because the whole team will look incompetent. I was told not do anything and reassigned to the completely different tasks far from the team. After another month, I left.