diff --git a/app/models/champs/linked_drop_down_list_champ.rb b/app/models/champs/linked_drop_down_list_champ.rb
index 355f44442..157f4af89 100644
--- a/app/models/champs/linked_drop_down_list_champ.rb
+++ b/app/models/champs/linked_drop_down_list_champ.rb
@@ -41,7 +41,11 @@ class Champs::LinkedDropDownListChamp < Champ
   end
 
   def primary_value=(value)
-    pack_value(value, secondary_value)
+    if value.blank?
+      pack_value("", "")
+    else
+      pack_value(value, secondary_value)
+    end
   end
 
   def secondary_value=(value)
diff --git a/spec/models/champs/linked_drop_down_list_champ_spec.rb b/spec/models/champs/linked_drop_down_list_champ_spec.rb
index 9d0977716..bf53cc1b4 100644
--- a/spec/models/champs/linked_drop_down_list_champ_spec.rb
+++ b/spec/models/champs/linked_drop_down_list_champ_spec.rb
@@ -14,6 +14,14 @@ describe Champs::LinkedDropDownListChamp do
     it { expect(champ.value).to eq('["tata","tutu"]') }
   end
 
+  describe '#primary_value=' do
+    let!(:champ) { described_class.new(primary_value: 'tata', secondary_value: 'tutu') }
+
+    before { champ.primary_value = '' }
+
+    it { expect(champ.value).to eq('["",""]') }
+  end
+
   describe '#to_s' do
     let(:champ) { described_class.new(primary_value: primary_value, secondary_value: secondary_value) }
     let(:primary_value) { nil }