There is a case in which I would expect this behaviour. I'm going to give a specific example because I'm not sure I can explain it without it. I'll make it generic and non-commercial as possible.
Let's say you want to search for "going post" which is the name of a band. You type it in but the results are for "going postal" which is a much more common search query. Then when you hit enter Google realizes that you actually meant "going post" and not "going postal" and switches the results to what you want.