diff --git a/mcrouter/lib/carbon/example/gen/HelloGoodbyeThriftTransport.h b/mcrouter/lib/carbon/example/gen/HelloGoodbyeThriftTransport.h
index 30cf7754d..733b8b859 100644
--- a/mcrouter/lib/carbon/example/gen/HelloGoodbyeThriftTransport.h
+++ b/mcrouter/lib/carbon/example/gen/HelloGoodbyeThriftTransport.h
@@ -257,7 +257,7 @@ class ThriftTransport<hellogoodbye::HelloGoodbyeRouterInfo> : public ThriftTrans
   apache::thrift::Client<hellogoodbye::thrift::HelloGoodbye>* getThriftClient() {
     if (FOLLY_UNLIKELY(!thriftClient_)) {
       thriftClient_ = createThriftClient<apache::thrift::Client<hellogoodbye::thrift::HelloGoodbye>>();
-      if (flushList_) {
+      if (thriftClient_.has_value() && flushList_) {
         auto* channel = static_cast<apache::thrift::RocketClientChannel*>(
             thriftClient_->getChannel());
         channel->setFlushList(flushList_);
diff --git a/mcrouter/lib/carbon/test/gen/AThriftTransport.h b/mcrouter/lib/carbon/test/gen/AThriftTransport.h
index 5b6c390e0..b9bc1660d 100644
--- a/mcrouter/lib/carbon/test/gen/AThriftTransport.h
+++ b/mcrouter/lib/carbon/test/gen/AThriftTransport.h
@@ -176,7 +176,7 @@ class ThriftTransport<carbon::test::A::ARouterInfo> : public ThriftTransportMeth
   apache::thrift::Client<carbon::test::A::thrift::A>* getThriftClient() {
     if (FOLLY_UNLIKELY(!thriftClient_)) {
       thriftClient_ = createThriftClient<apache::thrift::Client<carbon::test::A::thrift::A>>();
-      if (flushList_) {
+      if (thriftClient_.has_value() && flushList_) {
         auto* channel = static_cast<apache::thrift::RocketClientChannel*>(
             thriftClient_->getChannel());
         channel->setFlushList(flushList_);
diff --git a/mcrouter/lib/carbon/test/gen/BThriftTransport.h b/mcrouter/lib/carbon/test/gen/BThriftTransport.h
index 228a9e1d4..386c0f3b0 100644
--- a/mcrouter/lib/carbon/test/gen/BThriftTransport.h
+++ b/mcrouter/lib/carbon/test/gen/BThriftTransport.h
@@ -176,7 +176,7 @@ class ThriftTransport<carbon::test::B::BRouterInfo> : public ThriftTransportMeth
   apache::thrift::Client<carbon::test::B::thrift::B>* getThriftClient() {
     if (FOLLY_UNLIKELY(!thriftClient_)) {
       thriftClient_ = createThriftClient<apache::thrift::Client<carbon::test::B::thrift::B>>();
-      if (flushList_) {
+      if (thriftClient_.has_value() && flushList_) {
         auto* channel = static_cast<apache::thrift::RocketClientChannel*>(
             thriftClient_->getChannel());
         channel->setFlushList(flushList_);
diff --git a/mcrouter/lib/carbon/test/gen/CarbonTestThriftTransport.h b/mcrouter/lib/carbon/test/gen/CarbonTestThriftTransport.h
index 722476571..30e3b8f5d 100644
--- a/mcrouter/lib/carbon/test/gen/CarbonTestThriftTransport.h
+++ b/mcrouter/lib/carbon/test/gen/CarbonTestThriftTransport.h
@@ -231,7 +231,7 @@ class ThriftTransport<carbon::test::CarbonTestRouterInfo> : public ThriftTranspo
   apache::thrift::Client<carbon::test::thrift::CarbonTest>* getThriftClient() {
     if (FOLLY_UNLIKELY(!thriftClient_)) {
       thriftClient_ = createThriftClient<apache::thrift::Client<carbon::test::thrift::CarbonTest>>();
-      if (flushList_) {
+      if (thriftClient_.has_value() && flushList_) {
         auto* channel = static_cast<apache::thrift::RocketClientChannel*>(
             thriftClient_->getChannel());
         channel->setFlushList(flushList_);
diff --git a/mcrouter/lib/carbon/test/gen/CarbonThriftTestThriftTransport.h b/mcrouter/lib/carbon/test/gen/CarbonThriftTestThriftTransport.h
index c1b641093..a1126d870 100644
--- a/mcrouter/lib/carbon/test/gen/CarbonThriftTestThriftTransport.h
+++ b/mcrouter/lib/carbon/test/gen/CarbonThriftTestThriftTransport.h
@@ -286,7 +286,7 @@ class ThriftTransport<carbon::test::CarbonThriftTestRouterInfo> : public ThriftT
   apache::thrift::Client<carbon::test::thrift::CarbonThriftTest>* getThriftClient() {
     if (FOLLY_UNLIKELY(!thriftClient_)) {
       thriftClient_ = createThriftClient<apache::thrift::Client<carbon::test::thrift::CarbonThriftTest>>();
-      if (flushList_) {
+      if (thriftClient_.has_value() && flushList_) {
         auto* channel = static_cast<apache::thrift::RocketClientChannel*>(
             thriftClient_->getChannel());
         channel->setFlushList(flushList_);
diff --git a/mcrouter/lib/network/gen/MemcacheThriftTransport.h b/mcrouter/lib/network/gen/MemcacheThriftTransport.h
index 386bec482..99b1c6e20 100644
--- a/mcrouter/lib/network/gen/MemcacheThriftTransport.h
+++ b/mcrouter/lib/network/gen/MemcacheThriftTransport.h
@@ -1166,7 +1166,7 @@ class ThriftTransport<MemcacheRouterInfo> : public ThriftTransportMethods<Memcac
   apache::thrift::Client<facebook::memcache::thrift::Memcache>* getThriftClient() {
     if (FOLLY_UNLIKELY(!thriftClient_)) {
       thriftClient_ = createThriftClient<apache::thrift::Client<facebook::memcache::thrift::Memcache>>();
-      if (flushList_) {
+      if (thriftClient_.has_value() && flushList_) {
         auto* channel = static_cast<apache::thrift::RocketClientChannel*>(
             thriftClient_->getChannel());
         channel->setFlushList(flushList_);