diff --git a/sale_order_type/models/account_move.py b/sale_order_type/models/account_move.py
index e2e2211735b..2966e89fcca 100644
--- a/sale_order_type/models/account_move.py
+++ b/sale_order_type/models/account_move.py
@@ -46,9 +46,15 @@ def _compute_sale_type_id(self):
 
     @api.depends("sale_type_id")
     def _compute_invoice_payment_term_id(self):
+        previous = {move: move.invoice_payment_term_id for move in self}
         res = super()._compute_invoice_payment_term_id()
-        for move in self.filtered("sale_type_id.payment_term_id"):
-            move.invoice_payment_term_id = move.sale_type_id.payment_term_id
+        for move in self:
+            if move.sale_type_id.payment_term_id:
+                move.invoice_payment_term_id = move.sale_type_id.payment_term_id
+            else:
+                previous_term = previous.get(move)
+                if previous_term:
+                    move.invoice_payment_term_id = previous_term
         return res
 
     @api.depends("sale_type_id")
diff --git a/sale_order_type/tests/test_sale_order_type.py b/sale_order_type/tests/test_sale_order_type.py
index 9a5a9584959..882690e0697 100644
--- a/sale_order_type/tests/test_sale_order_type.py
+++ b/sale_order_type/tests/test_sale_order_type.py
@@ -191,6 +191,33 @@ def test_invoice_onchange_type(self):
         self.assertEqual(invoice.invoice_payment_term_id, sale_type.payment_term_id)
         self.assertEqual(invoice.journal_id, sale_type.journal_id)
 
+    def test_invoice_change_journal_keeps_manual_payment_term(self):
+        partner = self.env["res.partner"].create(
+            {
+                "name": "Invoice Term Test Partner",
+                "property_payment_term_id": self.immediate_payment.id,
+            }
+        )
+        manual_payment_term = self.env.ref("account.account_payment_term_30days")
+        sale_type_without_payment_term = self.sale_type.copy(
+            {"name": "Sale Type Without Payment Term", "payment_term_id": False}
+        )
+        other_journal = self.env["account.journal"].create(
+            {
+                "name": "Alternative Sales Journal",
+                "code": "ASJ1",
+                "type": "sale",
+                "company_id": self.env.company.id,
+            }
+        )
+        invoice = self.invoice_model.new()
+        invoice.partner_id = partner
+        invoice.sale_type_id = sale_type_without_payment_term
+        invoice.invoice_payment_term_id = manual_payment_term
+        invoice.journal_id = other_journal
+        self.assertEqual(invoice.journal_id, other_journal)
+        self.assertEqual(invoice.invoice_payment_term_id, manual_payment_term)
+
     def test_invoice_change_partner(self):
         invoice = self.create_invoice()
         self.assertEqual(invoice.sale_type_id, self.sale_type)