diff --git a/app/helpers/schemes_helper.rb b/app/helpers/schemes_helper.rb
index 1133d201c..7efb9fffd 100644
--- a/app/helpers/schemes_helper.rb
+++ b/app/helpers/schemes_helper.rb
@@ -88,6 +88,7 @@ module SchemesHelper
   def display_duplicate_schemes_banner?(organisation, current_user)
     return unless organisation.absorbed_organisations.merged_during_open_collection_period.any?
     return unless current_user.data_coordinator? || current_user.support?
+    return if organisation.schemes_deduplicated_at.present? && organisation.schemes_deduplicated_at > organisation.absorbed_organisations.map(&:merge_date).max
 
     organisation.owned_schemes.duplicate_sets.any? || organisation.owned_schemes.any? { |scheme| scheme.locations.duplicate_sets.any? }
   end
diff --git a/spec/helpers/schemes_helper_spec.rb b/spec/helpers/schemes_helper_spec.rb
index 0a37a1b38..8ffde636a 100644
--- a/spec/helpers/schemes_helper_spec.rb
+++ b/spec/helpers/schemes_helper_spec.rb
@@ -137,7 +137,7 @@ RSpec.describe SchemesHelper do
 
     context "when organisation has absorbed other organisations in open collection year" do
       before do
-        build(:organisation, merge_date: Time.zone.today, absorbing_organisation_id: organisation.id).save(validate: false)
+        build(:organisation, merge_date: Time.zone.yesterday, absorbing_organisation_id: organisation.id).save(validate: false)
       end
 
       context "and it has duplicate schemes" do
@@ -148,6 +148,26 @@ RSpec.describe SchemesHelper do
         it "displays the banner" do
           expect(display_duplicate_schemes_banner?(organisation, current_user)).to be_truthy
         end
+
+        context "and organisation has confirmed duplicate schemes after the most recent merge" do
+          before do
+            organisation.update!(schemes_deduplicated_at: Time.zone.today)
+          end
+
+          it "does not display the banner" do
+            expect(display_duplicate_schemes_banner?(organisation, current_user)).to be_falsey
+          end
+        end
+
+        context "and organisation has confirmed duplicate schemes before the most recent merge" do
+          before do
+            organisation.update!(schemes_deduplicated_at: Time.zone.today - 2.days)
+          end
+
+          it "displays the banner" do
+            expect(display_duplicate_schemes_banner?(organisation, current_user)).to be_truthy
+          end
+        end
       end
 
       context "and it has duplicate locations" do