diff --git a/libraries/chain/db_block.cpp b/libraries/chain/db_block.cpp
index 15c95378..29b0eeaf 100644
--- a/libraries/chain/db_block.cpp
+++ b/libraries/chain/db_block.cpp
@@ -42,24 +42,26 @@
 
 namespace {
     
-    struct proposed_operations_digest_accumulator
-    {
-        typedef void result_type;
-        
-        template<class T>
-        void operator()(const T&) 
-        {}
-        
-        void operator()(const graphene::chain::proposal_create_operation& proposal)
-        {
-            for (auto& operation: proposal.proposed_ops)
-            {
-                proposed_operations_digests.push_back(fc::digest(operation.op));
-            }
-        }
-        
-        std::vector<fc::sha256> proposed_operations_digests;
-    };
+   struct proposed_operations_digest_accumulator
+   {
+      typedef void result_type;
+      
+      void operator()(const graphene::chain::proposal_create_operation& proposal)
+      {
+         for (auto& operation: proposal.proposed_ops)
+         {
+            proposed_operations_digests.push_back(fc::digest(operation.op));
+         }
+      }
+       
+      //empty template method is needed for all other operation types
+      //we can ignore them, we are interested in only proposal_create_operation
+      template<class T>
+      void operator()(const T&) 
+      {}
+      
+      std::vector<fc::sha256> proposed_operations_digests;
+   };
 }
 
 namespace graphene { namespace chain {
diff --git a/tests/tests/network_broadcast_api_tests.cpp b/tests/tests/network_broadcast_api_tests.cpp
index f50b61e5..e438e76b 100644
--- a/tests/tests/network_broadcast_api_tests.cpp
+++ b/tests/tests/network_broadcast_api_tests.cpp
@@ -27,6 +27,8 @@
 #include <graphene/chain/exceptions.hpp>
 #include <graphene/chain/protocol/proposal.hpp>
 #include <graphene/chain/proposal_object.hpp>
+#include <graphene/chain/witness_object.hpp>
+#include <graphene/chain/protocol/committee_member.hpp>
 #include <fc/crypto/digest.hpp>
 
 #include "../common/database_fixture.hpp"
@@ -46,6 +48,16 @@ namespace
         return transfer;
     }
     
+    committee_member_create_operation make_committee_member_create_operation(const asset& fee, const account_id_type& member, const string& url)
+    {
+        committee_member_create_operation member_create_operation;
+        member_create_operation.fee = fee;
+        member_create_operation.committee_member_account = member;
+        member_create_operation.url = url;
+        
+        return member_create_operation;
+    }
+    
     void create_proposal(database_fixture& fixture, const std::vector<operation>& operations)
     {
         signed_transaction transaction;
@@ -188,4 +200,58 @@ BOOST_AUTO_TEST_CASE( check_fails_for_duplicated_operation_in_existed_proposal_w
     }
 }
 
+BOOST_AUTO_TEST_CASE( check_passes_for_different_operations_types )
+{
+    try
+    {
+        ACTORS((alice))
+        
+        create_proposal(*this, {make_transfer_operation(account_id_type(), alice_id, asset(500))});
+        
+        auto trx = make_signed_transaction_with_proposed_operation(*this, {make_committee_member_create_operation(asset(1000), account_id_type(), "test url")});
+        BOOST_CHECK_NO_THROW(db.check_tansaction_for_duplicated_operations(trx));
+    }
+    catch( const fc::exception& e )
+    {
+        edump((e.to_detail_string()));
+        throw;
+    }
+}
+
+BOOST_AUTO_TEST_CASE( check_fails_for_same_member_create_operations )
+{
+    try
+    {
+        ACTORS((alice))
+        
+        create_proposal(*this, {make_committee_member_create_operation(asset(1000), account_id_type(), "test url")});
+        
+        auto trx = make_signed_transaction_with_proposed_operation(*this, {make_committee_member_create_operation(asset(1000), account_id_type(), "test url")});
+        BOOST_CHECK_THROW(db.check_tansaction_for_duplicated_operations(trx), fc::exception);
+    }
+    catch( const fc::exception& e )
+    {
+        edump((e.to_detail_string()));
+        throw;
+    }
+}
+
+BOOST_AUTO_TEST_CASE( check_passes_for_different_member_create_operations )
+{
+    try
+    {
+        ACTORS((alice))
+        
+        create_proposal(*this, {make_committee_member_create_operation(asset(1000), account_id_type(), "test url")});
+        
+        auto trx = make_signed_transaction_with_proposed_operation(*this, {make_committee_member_create_operation(asset(1001), account_id_type(), "test url")});
+        BOOST_CHECK_NO_THROW(db.check_tansaction_for_duplicated_operations(trx));
+    }
+    catch( const fc::exception& e )
+    {
+        edump((e.to_detail_string()));
+        throw;
+    }
+}
+
 BOOST_AUTO_TEST_SUITE_END()