After you copied an object you need to paste as Definition copy in order to create a new object:
When you only copy & paste objects e.g. via Ctrl+C/Ctrl+V then ARIS assumes you want an so called occurrence copy which is simply the same object just as duplicated shape. It still refers to the same definition copy which means that changing attributes of an object, such as the object's name, would change the name for ALL occurrences of that object. And that counts not only for the currently open model but also to all other models where that object occurs.
