Stock reduce twice

I have for the last months had a lot of problems with my inventory, because the stock levels was reducing twice when a new order was placed.
I have tried to deactivate all plugins and activated it one by one after testing with a new order, and it seems it only is a problem when the order is placed through your plugin (and not with BACS or Paypal).

I outcommented this function in paymill/lib/integration/woocommerce.inc.php

// Reduce stock levels
if(method_exists($this->order, ‘reduce_order_stock’)){
$this->order->reduce_order_stock();
}

It seems to work correctly now.

https://wordpress.org/plugins/paymill/