diff --git a/spec/services/bulk_upload/lettings/year2023/csv_parser_spec.rb b/spec/services/bulk_upload/lettings/year2023/csv_parser_spec.rb
index 084df9b1d..9c18e98d4 100644
--- a/spec/services/bulk_upload/lettings/year2023/csv_parser_spec.rb
+++ b/spec/services/bulk_upload/lettings/year2023/csv_parser_spec.rb
@@ -106,6 +106,31 @@ RSpec.describe BulkUpload::Lettings::Year2023::CsvParser do
     end
   end
 
+  context "when parsing csv with too few valid headers" do
+    let(:seed) { rand }
+    let(:log_to_csv) { BulkUpload::LogToCsv.new(log:) }
+    let(:field_numbers) { log_to_csv.default_2023_field_numbers }
+    let(:field_values) { log_to_csv.to_2023_row }
+
+    before do
+      field_numbers.delete_at(20)
+      field_values.delete_at(20)
+      file.write("Question\n")
+      file.write("Additional info\n")
+      file.write("Values\n")
+      file.write("Can be empty?\n")
+      file.write("Type of letting the question applies to\n")
+      file.write("Duplicate check field?\n")
+      file.write(log_to_csv.custom_2023_field_numbers_row(seed:, field_numbers:))
+      file.write(log_to_csv.to_custom_2023_csv_row(seed:, field_values:))
+      file.rewind
+    end
+
+    it "counts the number of valid field numbers correctly" do
+      expect(service.valid_field_numbers_count).to eql(133)
+    end
+  end
+
   context "when parsing csv without headers" do
     before do
       file.write(BulkUpload::LogToCsv.new(log:, col_offset: 0).to_2023_csv_row)