In the future, when posting code, please UseCodeTags(←click). This will make your code more readable, and will automatically add line numbers.
As for your question, there's nothing random about it. You're passing a reference to an array of doubles to the constructor--the exact doubles that you're seeing printed out for v2. Presumably that Vector constructor iterates through the array, adding each element to itself. This is exactly the behavior I'd expect.
Why are you using Vector? Have you got an old book? Vector has been legacy code for about 12 years.
Why are you not parametrising the Vector? I think you must tell us where the question is from before we can understand it fully. That is because some books introduce confusing elements into questions. You would do well to read the documentation for Vector, which may help you understand what is happening.