diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index a57e313e2e9..7761dc832de 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -2720,9 +2720,11 @@ def create_dunning(source_name, target_doc=None, ignore_permissions=False):
 				target.closing_text = letter_text.get("closing_text")
 				target.language = letter_text.get("language")
 
-		# update outstanding
+		# update outstanding from doc
 		if source.payment_schedule and len(source.payment_schedule) == 1:
-			target.overdue_payments[0].outstanding = source.get("outstanding_amount")
+			for row in target.overdue_payments:
+				if row.payment_schedule == source.payment_schedule[0].name:
+					row.outstanding = source.get("outstanding_amount")
 
 		target.validate()