I use the app Scarcity: Cart Countdown Timer in my store to prevent customers from leaving items in their carts. It seems to be working well. However, I had an instance yesterday when two different customers added the same variable product to their cart simultaneously. Therefore, they both thought they would be able to purchase in the allotted time.
Is there any way to prevent this from happening? Whether it be another app or some code to add? I would prefer once an item is added into a cart, the store would not allow someone else to add it to their cart also. I do all of my checkout process through the store via Shopify Checkout and PayPal Express Checkout.