[FIX] filter discount

model/account.py

@@ -14,7 +14,7 @@ class AccountInvoice(models.Model):
 			return False
 
 		''' Move line'''
-		moveLines = self.env['account.move.line'].search([('invoice','=',invoice.id),('debit','>',0)], order='date_maturity')
+		moveLines = self.env['account.move.line'].search([('invoice','=',invoice.id),('debit','>',0),('date_maturity','!=', False)], order='date_maturity')
 
 		quotaCont = 0
 		for moveLine in moveLines: