You must add all necessary referral exclusions to get accurate marketing data for your orders. Without proper referral exclusions, order will be attributed to sites like shop.app and paypal.com.
Return to your Websites Data Stream settings and select "List unwanted referrals"
Click "Add condition"
Enter ALL referral exclusions, especially those from third-party checkout providers like Shop, PayPal and Recharge. All stores should add the "shop.app" referral exclusions. You can find your Universal Analytics referral exclusions under Admin > Tracking Info > Referral Exclusion List.