Bold Discounts - integrated with Bold Upsell - gives you the ability to offer Buy One Get One deals on your site using its duplicate & hide feature. This feature creates a hidden duplicate of the main version of your product(s). Discounts does this so you can offer discounted items, through Upsell, that aren't purchasable on their own.
When the duplicate version is purchased, Discounts will subtract inventory from both the duplicate and the main version of the item. However, when just the main version is purchased, the inventory is not reduced on our duplicate product. This is because Shopify does not communicate back with our servers to inform us of these purchases.
This means that the main version of your product(s) will always contain the true inventory numbers. Because Discounts deletes these duplicate items when the sale is turned off, these products technically act as placeholders. We want to ensure that the main product's inventory always remains true.
Visit Adjust Inventory Settings in Bold Discounts for more information on how to change these tracking settings.