diff --git a/addons/l10n_in/models/account_invoice.py b/addons/l10n_in/models/account_invoice.py
index 9944792b987..0762ad02169 100644
--- a/addons/l10n_in/models/account_invoice.py
+++ b/addons/l10n_in/models/account_invoice.py
@@ -57,7 +57,7 @@ class AccountMove(models.Model):
         res = super()._get_tax_grouping_key_from_tax_line(tax_line)
         if tax_line.move_id.journal_id.company_id.account_fiscal_country_id.code == 'IN':
             res['product_id'] = tax_line.product_id.id
-            res['product_uom_id'] = tax_line.product_uom_id
+            res['product_uom_id'] = tax_line.product_uom_id.id
             res['quantity'] = tax_line.quantity
         return res
 
@@ -67,7 +67,7 @@ class AccountMove(models.Model):
         res = super()._get_tax_grouping_key_from_base_line(base_line, tax_vals)
         if base_line.move_id.journal_id.company_id.account_fiscal_country_id.code == 'IN':
             res['product_id'] = base_line.product_id.id
-            res['product_uom_id'] = base_line.product_uom_id
+            res['product_uom_id'] = base_line.product_uom_id.id
             res['quantity'] = base_line.quantity
             res['id'] = base_line.id
         return res
@@ -78,7 +78,7 @@ class AccountMove(models.Model):
 
         tax_key += [
             line.product_id.id,
-            line.product_uom_id,
+            line.product_uom_id.id,
             line.quantity,
             line.id,
         ]