The common product details page have no way to add to cart even if it have the add to cart button

Do anyone have use the common products on your marketplace website, I found that the common product details page have no way to add to cart even if it have the add to cart button.
I think, if one common product was sold by several sellers/vendors, the common product details page should have a add to cart button to help customer buy it, The only question is that who the order belong to, Yes or no?
What we need do something for it?

Hello!

Unfortunately I could not understand how to reproduce the issue. Have you enabled the Buy a default common product option in the Common Products for Vendors add-on’s settings? Please note that it was added in the 4.14.2 version.

Please describe how to reproduce the issue in the step-by-step way. Also it will be great, if you will specify what behavior you are facing in this case and what behavior you are expecting.