diff --git a/lib/grape_entity/exposure/nesting_exposure/output_builder.rb b/lib/grape_entity/exposure/nesting_exposure/output_builder.rb
index 93afe3c1..add41e00 100644
--- a/lib/grape_entity/exposure/nesting_exposure/output_builder.rb
+++ b/lib/grape_entity/exposure/nesting_exposure/output_builder.rb
@@ -56,7 +56,7 @@ def merge_strategy(for_merge)
             if for_merge.respond_to? :call
               for_merge
             else
-              -> {}
+              ->(k, v1, v2){ v2 }
             end
           end
         end