diff --git a/stock_auto_move/models/stock_move.py b/stock_auto_move/models/stock_move.py
index bd483690c754..d217da7ec34f 100644
--- a/stock_auto_move/models/stock_move.py
+++ b/stock_auto_move/models/stock_move.py
@@ -30,10 +30,17 @@ def _get_auto_moves_by_pickings(self, auto_moves):
 
     @api.multi
     def action_assign(self, no_prepare=False):
-        res = super(StockMove, self).action_assign(no_prepare=no_prepare)
 
-        # Select auto moves that are assigned
-        auto_moves = self.filtered(
+        already_assigned_moves = self.filtered(
+            lambda m: m.state == 'assigned')
+
+        not_assigned_auto_move = self - already_assigned_moves
+
+        res = super(StockMove, self).action_assign(
+            no_prepare=no_prepare)
+
+        # Process only moves that have been processed recently
+        auto_moves = not_assigned_auto_move.filtered(
             lambda m: m.state == 'assigned' and m.auto_move)
 
         # group the moves by pickings