fix: Purchase Order creation from Sales Order
diff --git a/erpnext/selling/doctype/sales_order/sales_order.py b/erpnext/selling/doctype/sales_order/sales_order.py
index 8c03cb5..09a9652 100755
--- a/erpnext/selling/doctype/sales_order/sales_order.py
+++ b/erpnext/selling/doctype/sales_order/sales_order.py
@@ -892,6 +892,7 @@
 		target.additional_discount_percentage = 0.0
 		target.discount_amount = 0.0
 		target.inter_company_order_reference = ""
+		target.shipping_rule = ""
 
 		default_price_list = frappe.get_value("Supplier", supplier, "default_price_list")
 		if default_price_list:
@@ -1010,6 +1011,7 @@
 		target.additional_discount_percentage = 0.0
 		target.discount_amount = 0.0
 		target.inter_company_order_reference = ""
+		target.shipping_rule = ""
 		target.customer = ""
 		target.customer_name = ""
 		target.run_method("set_missing_values")