Problem with woocommerce import?

Question

WordPress

I import products via wp all import (plugin) there is a task to make some products by in stock/out of stock attribute. I ran into a problem that on each product the first variation is always set in stock (even if I manually set the import to set out of stock, it does nothing). Here for the following variations, everything is in order, it works. Why does such a problem even occur? Perhaps there is some setting in the admin panel.