diff --git a/src/cpp/ripple/LedgerHistory.cpp b/src/cpp/ripple/LedgerHistory.cpp
index 34a0d05d8..dc30e87e3 100644
--- a/src/cpp/ripple/LedgerHistory.cpp
+++ b/src/cpp/ripple/LedgerHistory.cpp
@@ -24,6 +24,7 @@ LedgerHistory::LedgerHistory() : mLedgersByHash("LedgerCache", CACHED_LEDGER_NUM
 
 void LedgerHistory::addLedger(Ledger::pointer ledger)
 {
+	assert(ledger->isImmutable());
 	mLedgersByHash.canonicalize(ledger->getHash(), ledger, true);
 }
 
@@ -78,13 +79,17 @@ Ledger::pointer LedgerHistory::getLedgerByHash(const uint256& hash)
 {
 	Ledger::pointer ret = mLedgersByHash.fetch(hash);
 	if (ret)
+	{
+		assert(ret->getHash() == hash);
 		return ret;
+	}
 
 	ret = Ledger::loadByHash(hash);
 	if (!ret)
 		return ret;
 	assert(ret->getHash() == hash);
 	mLedgersByHash.canonicalize(ret->getHash(), ret);
+	assert(ret->getHash() == hash);
 
 	return ret;
 }
diff --git a/src/cpp/ripple/LedgerMaster.h b/src/cpp/ripple/LedgerMaster.h
index 514b05551..dac64c862 100644
--- a/src/cpp/ripple/LedgerMaster.h
+++ b/src/cpp/ripple/LedgerMaster.h
@@ -105,10 +105,11 @@ public:
 	Ledger::pointer getLedgerByHash(const uint256& hash)
 	{
 		if (hash.isZero())
-			return mCurrentLedger;
+			return boost::make_shared<Ledger>(boost::ref(*mCurrentLedger), false);
 
 		if (mCurrentLedger && (mCurrentLedger->getHash() == hash))
-			return mCurrentLedger;
+			return boost::make_shared<Ledger>(boost::ref(*mCurrentLedger), false);
+
 		if (mFinalizedLedger && (mFinalizedLedger->getHash() == hash))
 			return mFinalizedLedger;