Enhanced e-commerce analytics double after cancellation

Hello,

we have installed the free GTM extension (https://www.weltpixel.com/google-analytics-enhanced-ecommerce-tag-manager-magento-2.html) and we get double amounts in enhanced e-commerce analytics when an order is cancelled. 

For example if a client places an order with qty 100 and price 10 per item (1000 total), we will get in analytics 2000 total(200 items X 10).