Layout & page title issues

I really like this plugin because I think it has some great features, but for the life of me, I can’t get this layout to display correctly, and I’m getting some weird page-naming results. The name of the product is “Sheep’s Virtual Gift Card”, but the title of the page in my browser is showing “-1389”. My store is not public yet, so I cannot provide a link to the page.

Here is a link to the layout I’m seeing (default WC product page):

https://sheepsclothingknitting.com/wp-content/uploads/2020/11/Screenshot_2020-11-16-1389.png

Here is the page source code:

https://sheepsclothingknitting.com/wp-content/uploads/2020/11/yith-giftcard-layout-sourcecode.zip

Any help would be appreciated. I would really like to use this plugin.

Thanks!