TRIGGER BROWSER INSTANCE NOT SWAP - go to x.com
This link uses click event with preventDefault and window.location.replace. It goes to https://x.com.
On the back button, we get bfcache not restored reason as: BrowsingInstanceNotSwapped in Application Tab.

      addEventListener('click', function(e){
        e.preventDefault();
        window.location.hash = "test";
        window.location.replace(e.target.getAttribute('href'));
      });
      

TRIGGER UNKNOWN - go to www.google.com
This link uses click event with preventDefault and window.location.replace. It goes to https://www.google.com.
On the back button, we get bfcache not restored reason as: Unknown in Application Tab.

      addEventListener('click', function(e){
        e.preventDefault();
        window.location.hash = "test";
        window.location.replace(e.target.getAttribute('href'));
      });
      

The two examples above return a masked not restored reason from javascript API. It's shown above them.

NOT PREVENT BfCache
This link uses click event with preventDefault and force click on newly added element to DOM. The link goes to https://www.google.com.
On the back button, we get success of BFCache.

      addEventListener('click', function(e){
        e.preventDefault();
        document.body.insertAdjacentHTML('beforeend', '<a class="clicker" href="' + e.target.getAttribute('href') + '"></a>');

        const clickEvent = new MouseEvent('click', {
            bubbles: false,  
            cancelable: false
        });

         document.body.querySelector('.clicker').dispatchEvent(clickEvent);
      });