While the other answers are good I would just add my perspective.
First, while it is unclear why you are asking this question, if you are asking as part of a post-mortem to see what you can do better next time, then it is good and yes, something clearly went wrong. If you are doing this so that blame can be assigned to the appropriate person then you should avoid this. Blaming rarely does anyone any good. Consider it a learning opportunity for everyone on the team. Blaming introduces fear which leads to (as Marv said) PM's burying the bad stuff (which always causes bigger problems down the road).
Second, problems do happen and (as Marv said quite well) how you react to problems is really what separates the strong PM's from the weak. There is a reason that when planning you should always include contingency time and money...because surprises often happen.