I have seen two issues hurting all kind of agile manifestations. One, it is difficult to build a mature team to really adopt agile. So you have certifications, that have created a group of people who think that they will lose their jobs if everyone else learns agile. They get in the way of the entire team participating in the process together. As a result, that person ends up being an adapter between whatever-process-the-team-is-actually-following and the agile that they are supposed to follow causing a lot of overheads. And agile is one concept that cannot be faked.