Unexpected segmentation fault when passing a non pointer type of variable to the constructor of a Node

Question

I am creating a Circular Linked List template class. I have an assignment operator that one Circular List to another. However, when I use a copy constructor to create a List and assign the original list to the copied list it generates a segmentation fault.

cout<<"cl: "<<cl<<endl;
cout<<endl<<"C
CircularList<int> cl2(cl);
cl=cl2;

I have tested this extensively using cout statements and isolated the line where the error occurs.

template <class T>
CircularList<T>& CircularList<T>::operator=(const CircularList<T> 
&other)
{
    this->clear();
    if(other.tail==NULL)
    {
        tail=NULL;
        return (*this);
    }
    Node<T> *ptr=other.tail;
    tail= new Node<T>(ptr->element);
    Node<T> *node=tail;
    while(ptr->next!=other.tail)
    {
        ptr=ptr->next;
        //a statement used for testing output
        cout<<ptr->element<<endl;
        node->next=new Node<T>(ptr->element); //segfault
        node=node->next;
    }
    node->next=tail;
    return *(this);
} 

The copy constructor:

template <class T>
CircularList<T>::CircularList(const CircularList<T>& other)
{
    if(other.tail==NULL)
    {
        tail=NULL;
        return;
    }

    Node<T> *ptr=other.tail;
    tail= new Node<T>(ptr->element);
    Node<T> *node=tail;
    while(ptr->next!=other.tail)
    {
        ptr=ptr->next;
        node->next=new Node<T>(ptr->element,NULL);
        node=node->next;
    }
    node->next=tail;
}

The code for the Node constructor:

    Node(T data, Node<T>* n = 0)
    {
        //cout for testing
        cout<<data<<endl;
        element =data;
        next = n;
    }

When this code is run it generates the following output on an int instance of the class where the contents of the first list is [8,7,6,5,4,11,3,2,1,0]

cl: [8,7,6,5,4,11,3,2,1,0]

Copy constr: 
0
8
7
6
5
4
11
3
2
1
0
8
8
7
7
6
6
5
5
4
4
11
11
3
3
2
2
1
make: *** [makefile:5: run] Segmentation fault (core dumped)

All the data is read is outputted twice, once inside the operator= function and once inside the Node's constructor, except for the last 1 where the segmentation fault occurs.

The code does not enter the Node constructors block.

I appreciate any help. Thank you!

I created a github repository with the needed files to reproduce the error: https://github.com/precious-princess-peach/Circular_linked_list_test