Hello,
Compare functionality of our theme is designed to handle the stock availability in only two ways “In stock” or “Out of stock” so it counts the backorder products in the stock list that’s why it shows the backorders availability as “In Stock” when you compare items.
Product status as “on backorder”: https://jmp.sh/XjXqZyB
After comparing the availability status of the product whose status is “on backorder”: https://jmp.sh/26vFQnc
You are using an old version of theme as well as outdated plugins which are required by theme. Kindly update your theme as well as plugins. Also your screenshots not working for us. All of them are corrupted.
Please refer the Woocommerce documentation or their support on the backorder issue. This is Woocommerce functionality and our theme does not influence.
Best Regards.