diff --git a/frame_serialize/CBORStream2Serializer.cpp b/frame_serialize/CBORStream2Serializer.cpp
index c34872f7..97a2f8bd 100644
--- a/frame_serialize/CBORStream2Serializer.cpp
+++ b/frame_serialize/CBORStream2Serializer.cpp
@@ -675,7 +675,8 @@ void CBORStream2Serializer::SerializeSequenceEnd(const EndMessage& message) {
     CBOR_ENC(mapEncoder, "bkg_estimate", message.bkg_estimate);
 
     CBOR_ENC(mapEncoder, "rotation_lattice_type", message.rotation_lattice_type);
-    CBOR_ENC(mapEncoder, "rotation_lattice", message.rotation_lattice->GetVector());
+    if (message.rotation_lattice.has_value())
+        CBOR_ENC(mapEncoder, "rotation_lattice", message.rotation_lattice->GetVector());
     CBOR_ENC(mapEncoder, "image_scale_factor", message.scale_factor);
     cborErr(cbor_encoder_close_container(&encoder, &mapEncoder));