Woocommerce shipping methods drop down discard value after calculating shipping

I have a problem with my woocommerce setup, I have multiple shipping methods and showing them in dropdown list. When I change shipping method, ajax request sent and values being updated, that's fine. But when I select country, state, enter zip code and submit form to Update Totals, the shipping methods' dropdown become mad, and discards its previous selected value. I checked into session of woocommerce and "chosen_shipping_methods" is also changed. I also tries by displaying shipping methods using radio buttons, but no success! Anyone please let me know what is problem, and what should I do?

via Chebli Mohamed