Add where condition to filter out invalid labels with nil type

app/models/label.rb

@@ -33,7 +33,7 @@ class Label < ApplicationRecord
 
   default_scope { order(title: :asc) }
 
-  scope :templates, -> { where(template: true) }
+  scope :templates, -> { where(template: true, type: [Label.name, nil]) }
   scope :with_title, ->(title) { where(title: title) }
   scope :with_lists_and_board, -> { joins(lists: :board).merge(List.movable) }
   scope :on_project_boards, ->(project_id) { with_lists_and_board.where(boards: { project_id: project_id }) }

changelogs/unreleased/63730-fix-500-status-labels-pd.yml

+---
+title: Fix admin labels page when there are invalid records
+merge_request: 30885
+author:
+type: fixed

spec/models/label_spec.rb

@@ -193,4 +193,17 @@ describe Label do
       expect(described_class.optionally_subscribed_by(nil)).to match_array([label, label2])
     end
   end
+
+  describe '#templates' do
+    context 'with invalid template labels' do
+      it 'returns only valid template labels' do
+        create(:label)
+        # Project labels should not have template set to true
+        create(:label, template: true)
+        valid_template_label = described_class.create!(title: 'test', template: true, type: nil)
+
+        expect(described_class.templates).to eq([valid_template_label])
+      end
+    end
+  end
 end