cod fee does not go away if I choose incompatible shipping

I’ve been using smart cod for quite some time and never had any issues with it. Its a very well balanced plugin with lots of features. However, I only recently discovered a bug to it and is so subtle that I am not sure how long it’s been there. When someone goes to checkout to choose shipping and payment and chooses a compatible with cod payment method, the cod fee is added to the checkout. If they then choose another shipping method that is not compatible, the payment changes but the cod fee remains. The customer needs to click some other payment method and then the default one to clear the fee. That is confusing cause it looks as if the other payment methods also carry a cod fee. Could you please look into this? Thank you oso much The page I need help with: [ log in to see the link]