diff --git a/GPy/core/parameterization/ties_and_remappings.py b/GPy/core/parameterization/ties_and_remappings.py
index a81b8d61..b06b4a2e 100644
--- a/GPy/core/parameterization/ties_and_remappings.py
+++ b/GPy/core/parameterization/ties_and_remappings.py
@@ -57,6 +57,9 @@ class Tie(Parameterized):
     
     """
     def __init__(self, name='tie'):
+        # whether it has just propagated tied parameter values during optimization
+        # If ture, it does not need to check consistency
+        self._PROPAGATE_VAL_ = False
         super(Tie, self).__init__(name)
         self.tied_param = None
         # The buffer keeps track of tie status
@@ -189,23 +192,33 @@ class Tie(Parameterized):
                 b0 = self.label_buf==self.label_buf[self.buf_idx[i]]
                 b = self._highest_parent_.param_array[b0]!=self.tied_param[i]
                 if b.sum()==0:
-                    print 'XXX'
+                    # All the tied parameters are the same
                     continue
                 elif b.sum()==1:
-                    print '!!!'
+                    # One of the tied parameter is different.
+                    # It must be recently changed one.
+                    # The rest will be set to its value.
                     val = self._highest_parent_.param_array[b0][b][0]
                     self._highest_parent_.param_array[b0] = val
                 else:
-                    print '@@@'
+                    # It is most likely that the tie parameter is changed.
+                    # Set all the tied parameter to the value of tie parameter.
                     self._highest_parent_.param_array[b0] = self.tied_param[i]
                 changed = True
         return changed
+    
+    def _parameters_changed_notification(self, me, which=None):
+        if which is not self:
+            self._optimizer_copy_transformed = False # tells the optimizer array to update on next request
+            self.parameters_changed()
 
     def parameters_changed(self):
         #ensure all out parameters have the correct value, as specified by our mapping
-        changed = self._check_change()
-        if changed:
-            self._highest_parent_._trigger_params_changed()
+        if self._PROPAGATE_VAL_:
+            self._PROPAGATE_VAL_ = False
+        else:
+            if self._check_change():
+                self._highest_parent_._trigger_params_changed()
         self.collate_gradient()
 
     def collate_gradient(self):
@@ -218,6 +231,7 @@ class Tie(Parameterized):
         if self.tied_param is not None:
             for i in xrange(self.tied_param.size):
                 self._highest_parent_.param_array[self.label_buf==self.label_buf[self.buf_idx[i]]] = self.tied_param[i]
+        self._PROPAGATE_VAL_ = True