diff --git a/app/models/post/template_field.rb b/app/models/post/template_field.rb
index a535c0c..b77ce49 100644
--- a/app/models/post/template_field.rb
+++ b/app/models/post/template_field.rb
@@ -288,7 +288,7 @@ class Post
           _value = [(_value.first + value).uniq]
         elsif _value.count == 2
           _value = _value.each_with_index.map do |v,i|
-            v + value[i]
+            v + value.fetch(i, [])
           end
         end
       end