Integrate with WooCommerce Simple Auction is_purchasable, is_sold_individually

Hi Team,
I am just make my site work between WCFM and WooCommerce Simple Auction.
There’s problem with my existing site.
I can add auction from WCFM and declare all the price perfectly like price per bid, starting price, reserve price, everythings are okay and i can ensure that they are well saved in MYSQL. And here’s a problem.
Suppose when there’s “Buy it now price”, there’s will be a “Buy it now” button on the single product page, it allows customer to checkout that auction directly without any biddings with others.
But actually i found out the “Buy it now” button doesn’t shown up, after I checked, the product which add from WCFM is without these two attributes:
1) global $product->is_purchasable = false;
2) global $product->is_sold_individually = false;
These two bool determine the button display or not in WooCommerce Simple Auction plugin.
I’ve also tried add auction by using wp-admin’s page and WCVendor’s add product page, both of them can give me is_purchasable = true and is_sold_individually = true.
May i know is it a bug or something i messed up?
Thanks WCLover Team