Internal QUICHE change

PiperOrigin-RevId: 364626603
Change-Id: I58cf500e74b114a89408409a6c6914080243effc
diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index e02b981..d323768 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -51,7 +51,7 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_h3_datagram, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_pass_path_response_to_validator, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_preempt_stream_data_with_handshake_packet, true)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_reject_unexpected_ietf_frame_types, false)
+QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_reject_unexpected_ietf_frame_types, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_require_handshake_confirmation, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_send_path_response2, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_send_timestamps, false)