Hi, and welcome to the Ranch!
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.