Problem with inventory in woocommerce?

Question

WordPress

Problem.
I am using WooCommerce.
I have items with limited inventory. For example 3 pieces.
There is a Test Payment Module for Woocommerce plugin for payment simulation.
If you select the quantity of goods 1 on the store page, and go through Checkout, choosing Test Payment as a payment, then as a result, if you check in the order in "Orders", then the following picture will appear: the inventory has decreased twice in succession.
If I had 4 items, and I chose 4 items to order, my total inventory would be -4.
The Woocommerce plugin was installed by the theme itself, not from the market.
I also installed the theme itself and TestPayment on a personal test local server, and the situation is similar.
Question: what could be the reason for this?

Answer 1

install this gateway https://uk.wordpress.org/plugins/without-payment-f... and try again