diff --git a/config/config.go b/config/config.go
index c768b00b2fe..958820a86f3 100644
--- a/config/config.go
+++ b/config/config.go
@@ -792,14 +792,13 @@ func DefaultMempoolConfig() *MempoolConfig {
 		WalPath:   "",
 		// Each signature verification takes .5ms, Size reduced until we implement
 		// ABCI Recheck
-		Size:         5000,
-		MaxTxsBytes:  1024 * 1024 * 1024, // 1GB
-		CacheSize:    10000,
-		MaxTxBytes:   1024 * 1024, // 1MB
-		TTLDuration:  0 * time.Second,
-		TTLNumBlocks: 0,
-		// Note this is true to avoid re-processing invalid order transactions more than once.
-		KeepInvalidTxsInCache: true,
+		Size:                  5000,
+		MaxTxsBytes:           1024 * 1024 * 1024, // 1GB
+		CacheSize:             10000,
+		MaxTxBytes:            1024 * 1024, // 1MB
+		TTLDuration:           0 * time.Second,
+		TTLNumBlocks:          0,
+		KeepInvalidTxsInCache: false,
 	}
 }
 
diff --git a/mempool/dydx_helpers.go b/mempool/dydx_helpers.go
index 8ec554e3153..18513b1847b 100644
--- a/mempool/dydx_helpers.go
+++ b/mempool/dydx_helpers.go
@@ -19,7 +19,8 @@ func IsClobOrderTransaction(
 		return false
 	}
 
-	if len(cosmosTx.Body.Messages) == 1 &&
+	if cosmosTx.Body != nil &&
+		len(cosmosTx.Body.Messages) == 1 &&
 		(cosmosTx.Body.Messages[0].TypeUrl == "/dydxprotocol.clob.MsgPlaceOrder" ||
 			cosmosTx.Body.Messages[0].TypeUrl == "/dydxprotocol.clob.MsgCancelOrder") {
 		return true
diff --git a/state/execution_test.go b/state/execution_test.go
index 5ae3c3c8723..23a602606ea 100644
--- a/state/execution_test.go
+++ b/state/execution_test.go
@@ -562,11 +562,13 @@ func TestEndBlockValidatorUpdatesResultingInEmptySet(t *testing.T) {
 	stateStore := sm.NewStore(stateDB, sm.StoreOptions{
 		DiscardABCIResponses: false,
 	})
+	mempoolMock := new(mpmocks.Mempool)
+
 	blockExec := sm.NewBlockExecutor(
 		stateStore,
 		log.TestingLogger(),
 		proxyApp.Consensus(),
-		new(mpmocks.Mempool),
+		mempoolMock,
 		sm.EmptyEvidencePool{},
 	)
 
@@ -582,6 +584,11 @@ func TestEndBlockValidatorUpdatesResultingInEmptySet(t *testing.T) {
 		{PubKey: vp, Power: 0},
 	}
 
+	// dYdX fork: Apply block should lock/unlock the mempool.
+	mempoolMock.On("Lock").Return()
+	mempoolMock.On("Unlock").Return()
+	mempoolMock.On("FlushAppConn").Return(nil)
+
 	assert.NotPanics(t, func() { state, _, err = blockExec.ApplyBlock(state, blockID, block) })
 	assert.NotNil(t, err)
 	assert.NotEmpty(t, state.NextValidators.Validators)