wp fastest cache does not allow redirect

Hello, we use fastest cache on our Divi related websites as it gives the best performance. Congratulations on that. We tried them all. Yours win!

However. using wp fastest cache it is impossible for us the ensure that people get redirected to the www. version of our site.

Enabling fastest cache and people surf to our site example.com see https://example.com in the address bar.

Disabling fastest cache and people surf to our site example.com see
https://www.example.com in the address bar.

Any idea why?

Thank you!