diff --git a/intern/cycles/blender/blender_curves.cpp b/intern/cycles/blender/blender_curves.cpp
index 8344684ac64..964241e9904 100644
--- a/intern/cycles/blender/blender_curves.cpp
+++ b/intern/cycles/blender/blender_curves.cpp
@@ -855,6 +855,7 @@ void BlenderSync::sync_hair(BL::Depsgraph b_depsgraph, BL::Object b_ob, Hair *ha
     hair->set_value(socket, new_hair, socket);
   }
 
+  hair->attributes.clear();
   foreach (Attribute &attr, new_hair.attributes.attributes) {
     hair->attributes.attributes.push_back(std::move(attr));
   }
diff --git a/intern/cycles/blender/blender_mesh.cpp b/intern/cycles/blender/blender_mesh.cpp
index 4bd4baec2e4..e85b4ee1fc6 100644
--- a/intern/cycles/blender/blender_mesh.cpp
+++ b/intern/cycles/blender/blender_mesh.cpp
@@ -1073,10 +1073,12 @@ void BlenderSync::sync_mesh(BL::Depsgraph b_depsgraph, BL::Object b_ob, Mesh *me
     mesh->set_value(socket, new_mesh, socket);
   }
 
+  mesh->attributes.clear();
   foreach (Attribute &attr, new_mesh.attributes.attributes) {
     mesh->attributes.attributes.push_back(std::move(attr));
   }
 
+  mesh->subd_attributes.clear();
   foreach (Attribute &attr, new_mesh.subd_attributes.attributes) {
     mesh->subd_attributes.attributes.push_back(std::move(attr));
   }