diff --git a/addons/crm/models/crm_lead.py b/addons/crm/models/crm_lead.py
index b25e2fc7c73..53abc9a4130 100644
--- a/addons/crm/models/crm_lead.py
+++ b/addons/crm/models/crm_lead.py
@@ -916,17 +916,19 @@ class Lead(models.Model):
           (still only active leads are considered). If False, search for active
           and not won leads and opportunities;
         """
-        if not email:
+        if not email and not partner:
             return self.env['crm.lead']
-        partner_match_domain = []
-        for email in set(email_split(email) + [email]):
-            partner_match_domain.append(('email_from', '=ilike', email))
+
+        domain = []
+        for normalized_email in [tools.email_normalize(email) for email in tools.email_split(email)]:
+            domain.append(('email_normalized', '=', normalized_email))
         if partner:
-            partner_match_domain.append(('partner_id', '=', partner.id))
-        partner_match_domain = ['|'] * (len(partner_match_domain) - 1) + partner_match_domain
-        if not partner_match_domain:
+            domain.append(('partner_id', '=', partner.id))
+        domain = ['|'] * (len(domain) - 1) + domain
+
+        if not domain:
             return self.env['crm.lead']
-        domain = partner_match_domain
+
         if include_lost:
             domain += ['|', ('type', '=', 'opportunity'), ('active', '=', True)]
         else:
diff --git a/addons/crm/tests/test_crm_lead_convert.py b/addons/crm/tests/test_crm_lead_convert.py
index 382d0a00055..3ebea3611af 100644
--- a/addons/crm/tests/test_crm_lead_convert.py
+++ b/addons/crm/tests/test_crm_lead_convert.py
@@ -262,9 +262,8 @@ class TestLeadConvert(crm_common.TestLeadConvertCommon):
             'active_ids': self.lead_1.ids,
         }).create({})
         self.assertEqual(convert.partner_id, self.customer)
-        # TDE FIXME: should not give priority to partner email if it is void
-        # self.assertEqual(convert.duplicated_lead_ids, self.lead_1 | lead_email_from | lead_email_normalized | lead_partner)
-        self.assertEqual(convert.duplicated_lead_ids, self.env['crm.lead'])
+        # self.assertEqual(convert.duplicated_lead_ids, self.lead_1 | self.lead_email_from | self.lead_email_normalized | self.lead_partner | self.opp_lost)
+        self.assertEqual(convert.duplicated_lead_ids, self.lead_1 | self.lead_email_from | self.lead_partner | self.opp_lost)
 
         # Check: partner fallbacks
         self.lead_1.write({
@@ -278,9 +277,7 @@ class TestLeadConvert(crm_common.TestLeadConvertCommon):
             'active_ids': self.lead_1.ids,
         }).create({})
         self.assertEqual(convert.partner_id, self.customer)
-        # TDE FIXME: CHECKME: 2917b38f28d5c2d6c53c706e613da7b8e2ad7b52 for lead without email
-        # self.assertEqual(convert.duplicated_lead_ids, self.lead_1 | lead_partner)
-        self.assertEqual(convert.duplicated_lead_ids, self.env['crm.lead'])
+        self.assertEqual(convert.duplicated_lead_ids, self.lead_1 | self.lead_partner)
 
     @users('user_sales_manager')
     def test_lead_merge_duplicates_flow(self):
diff --git a/addons/crm/wizard/crm_lead_to_opportunity.py b/addons/crm/wizard/crm_lead_to_opportunity.py
index b66ccf3e802..c47566a60ef 100644
--- a/addons/crm/wizard/crm_lead_to_opportunity.py
+++ b/addons/crm/wizard/crm_lead_to_opportunity.py
@@ -24,7 +24,7 @@ class Lead2OpportunityPartner(models.TransientModel):
             result['lead_id'] = lead.id
 
             partner = lead._find_matching_partner()
-            email = lead.partner_id.email if lead.partner_id else lead.email_from
+            email = lead.partner_id.email if lead.partner_id.email else lead.email_from
 
             tomerge.update(self.env['crm.lead']._get_lead_duplicates(partner, email, include_lost=True).ids)