if that is the old role, means wp (and hence plugins) was not notified of a move to the new role… makes it hard for any action to be taken…
worth verifying on the wishlist member settings that you have the wishlist levels properly mapped to wp roles… its not a wp or sp setting, but occurs within wishlist options for each level… and see what you have for the setting of removing levels when adding a new one…
another event you could add to the logging list for clarity if the wishlist hook when it adds a user level… add these two hooks to the event logging plugin:
wishlistmember_remove_user_levels
wishlistmember_add_user_levels
might give us better picture, in conjunction with the wp role change action, what is going on…