diff --git a/src/slic3r/GUI/PartPlate.cpp b/src/slic3r/GUI/PartPlate.cpp
index a1211f4692..4b52592f2d 100644
--- a/src/slic3r/GUI/PartPlate.cpp
+++ b/src/slic3r/GUI/PartPlate.cpp
@@ -4552,6 +4552,9 @@ int PartPlateList::create_plate(bool adjust_position)
 		return -1;
 	int cols = compute_colum_count(new_index + 1);
 	int old_cols = compute_colum_count(new_index);
+	// Orca: Rebuild plate membership before moving instances during a grid reflow.
+	if (adjust_position && old_cols != cols)
+		reload_all_objects();
 
 	origin = compute_origin(new_index, cols);
 	plate = new PartPlate(this, origin, m_plate_width, m_plate_depth, m_plate_height, m_plater, m_model, true, printer_technology);
@@ -5041,6 +5044,9 @@ int PartPlateList::move_plate_to_index(int old_index, int new_index)
 		return -1;
 	}
 
+	// Orca: Rebuild plate membership before moving the plates.
+	reload_all_objects();
+
 	if (old_index < new_index)
 	{
 		delta = 1;