diff --git a/app/services/project_identifiers/revert_project_to_classic_service.rb b/app/services/project_identifiers/revert_project_to_classic_service.rb
index 907e280b25a..26e21d3e297 100644
--- a/app/services/project_identifiers/revert_project_to_classic_service.rb
+++ b/app/services/project_identifiers/revert_project_to_classic_service.rb
@@ -51,24 +51,26 @@ module ProjectIdentifiers
     attr_reader :project
 
     def restore_classic_identifier
-      classic = identifier_generator.restore_identifier(project) ||
-                identifier_generator.suggest_identifier(project.name)
+      classic_id = identifier_generator.restore_identifier(project) ||
+                   identifier_generator.suggest_identifier(project.name)
       # Suppress notifications: this is a background system operation, not a user edit.
       Journal::NotificationConfiguration.with(false) do
-        project.update!(identifier: classic)
+        project.update!(identifier: classic_id)
       rescue ActiveRecord::RecordInvalid => e
-        handle_identifier_conflict(classic, e)
+        handle_update_failure(classic_id, e)
       end
     end
 
-    def handle_identifier_conflict(classic, error)
-      Rails.logger.warn "#{self.class}: identifier '#{classic}' taken for project #{project.id}, " \
-                        "falling back. (#{error.message})"
-      project.update!(identifier: identifier_generator.suggest_identifier(project.name))
+    def handle_update_failure(classic_id, error)
+      Rails.logger.warn "#{self.class}: Could not set identifier '#{classic_id}' for project #{project.id}; " \
+                        "falling back to a randomized suffix. (#{error.message})"
+      suffix = SecureRandom.alphanumeric(5).downcase
+      base = classic_id.first(Projects::Identifier::CLASSIC_IDENTIFIER_MAX_LENGTH - 6)
+      project.update!(identifier: "#{base}-#{suffix}")
     end
 
     def identifier_generator
-      ProjectIdentifiers::ClassicIdentifierSuggestionGenerator.new
+      @identifier_generator ||= ProjectIdentifiers::ClassicIdentifierSuggestionGenerator.new
     end
   end
 end
diff --git a/spec/services/project_identifiers/revert_project_to_classic_service_spec.rb b/spec/services/project_identifiers/revert_project_to_classic_service_spec.rb
index a67e01a5c9b..3b5f11fa59e 100644
--- a/spec/services/project_identifiers/revert_project_to_classic_service_spec.rb
+++ b/spec/services/project_identifiers/revert_project_to_classic_service_spec.rb
@@ -116,7 +116,13 @@ RSpec.describe ProjectIdentifiers::RevertProjectToClassicService do
       let!(:project) do
         create(:project).tap do |p|
           p.update_columns(identifier: "MYAPP", wp_sequence_counter: 0)
-          FriendlyId::Slug.create!(sluggable: p, slug: "my-app")
+          # Remove p's own initial slug so "my-app" is the only entry in its slug history.
+          # Without this, the factory slug (newer created_at) would be returned first by
+          # restore_identifier, the update would succeed, and the conflict path would never fire.
+          FriendlyId::Slug.where(sluggable_id: p.id, sluggable_type: "Project").delete_all
+          # blocking_project already owns the "my-app" FriendlyId slug; reassign it so that
+          # restore_identifier returns "my-app" and project.update! conflicts with blocking_project.
+          FriendlyId::Slug.where(slug: "my-app", sluggable_type: "Project").update_all(sluggable_id: p.id)
         end
       end
 
@@ -124,11 +130,9 @@ RSpec.describe ProjectIdentifiers::RevertProjectToClassicService do
         expect { described_class.new(project).call }.not_to raise_error
       end
 
-      it "assigns a valid classic identifier that is not the conflicting one" do
+      it "assigns the conflicting identifier with a 5-character random suffix" do
         described_class.new(project).call
-        reloaded = project.reload
-        expect(reloaded.identifier).to match(Projects::Identifier::CLASSIC_FORMAT)
-        expect(reloaded.identifier).not_to eq("my-app")
+        expect(project.reload.identifier).to match(/\Amy-app-[a-z0-9]{5}\z/)
       end
 
       it "logs a warning containing the project id and the conflicting identifier" do