diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 556faaa763..676d310f7b 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -5059,7 +5059,21 @@ void GLCanvas3D::do_move(const std::string& snapshot_type)
     }
 
     //BBS: notify instance updates to part plater list
-    m_selection.notify_instance_update(-1, 0);
+    // Only what moved: the selected instances, or every instance of an object one of whose
+    // parts moved. Notifying a plate about an instance that stayed put invalidates its slice
+    // result, and notifying instance 0 alone left a moved copy unregistered on its new plate.
+    {
+        std::set<std::pair<int, int>> notified;
+        for (unsigned int i : m_selection.get_volume_idxs()) {
+            const GLVolume* v          = m_volumes.volumes[i];
+            const int       object_idx = v->object_idx();
+            if (object_idx < 0 || object_idx >= static_cast<int>(m_model->objects.size()))
+                continue;
+            const std::pair<int, int> key(object_idx, selection_mode == Selection::Volume ? -1 : v->instance_idx());
+            if (notified.insert(key).second)
+                m_selection.notify_instance_update(key.first, key.second);
+        }
+    }
 
     // Fixes sinking/flying instances (snaps object to buildplate)
     for (const std::pair<int, int>& i : done) {
diff --git a/src/slic3r/GUI/PartPlate.cpp b/src/slic3r/GUI/PartPlate.cpp
index 9826498fbd..d38ab5e0ac 100644
--- a/src/slic3r/GUI/PartPlate.cpp
+++ b/src/slic3r/GUI/PartPlate.cpp
@@ -1917,7 +1917,7 @@ std::vector<int> PartPlate::get_extruders_without_support(bool conside_custom_gc
 	const DynamicPrintConfig& glb_config = wxGetApp().preset_bundle->prints.get_edited_preset().config;
 
 	for (int obj_idx = 0; obj_idx < m_model->objects.size(); obj_idx++) {
-		if (!contain_instance_totally(obj_idx, 0))
+		if (!contain_any_instance_totally(obj_idx))
 			continue;
 
 		ModelObject* mo = m_model->objects[obj_idx];
@@ -2088,7 +2088,7 @@ bool PartPlate::check_single_extruder_mixed_filament_risk(const DynamicPrintConf
                                             "which may significantly increase waste and the risk of nozzle / waste-chute clogging.");
 
     for (int obj_idx = 0; obj_idx < (int)m_model->objects.size(); ++obj_idx) {
-        if (!contain_instance_totally(obj_idx, 0))
+        if (!contain_any_instance_totally(obj_idx))
             continue;
         ModelObject *mo = m_model->objects[obj_idx];
         int obj_ext = mo->config.has("extruder") ? mo->config.extruder() : 1;
@@ -2307,7 +2307,7 @@ bool PartPlate::check_compatible_of_nozzle_and_filament(const DynamicPrintConfig
         return wipe_tower_size;
 
     for (int obj_idx = 0; obj_idx < m_model->objects.size(); obj_idx++) {
-        if (!use_global_objects && !contain_instance_totally(obj_idx, 0))
+        if (!use_global_objects && !contain_any_instance_totally(obj_idx))
             continue;
 
         BoundingBoxf3 bbox = m_model->objects[obj_idx]->bounding_box();
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index a28add0e4d..0fdb9dcd94 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -17839,6 +17839,10 @@ void Plater::increase_instances(size_t num)
         model_object->add_instance(offset_vec, model_instance->get_scaling_factor(), model_instance->get_rotation(), model_instance->get_mirror());
 //        p->print.get_object(obj_idx)->add_copy(Slic3r::to_2d(offset_vec));
     }
+    // Register the copies with the plate they land on before the scene reloads: the plate's
+    // filament list and wipe tower preview are read from that registry.
+    for (size_t i = model_object->instances.size() - num; i < model_object->instances.size(); ++i)
+        p->partplate_list.notify_instance_update(obj_idx, static_cast<int>(i));
 
 #ifdef SUPPORT_AUTO_CENTER
     if (p->get_config("autocenter") == "true")
@@ -17869,8 +17873,10 @@ void Plater::decrease_instances(size_t num)
 
     ModelObject* model_object = p->model.objects[obj_idx];
     if (model_object->instances.size() > num) {
-        for (size_t i = 0; i < num; ++ i)
+        for (size_t i = 0; i < num; ++ i) {
+            p->partplate_list.notify_instance_removed(obj_idx, static_cast<int>(model_object->instances.size()) - 1);
             model_object->delete_last_instance();
+        }
         p->update();
         // Delete object from Sidebar list. Do it after update, so that the GLScene selection is updated with the modified model.
         sidebar().obj_list()->decrease_object_instances(obj_idx, num);