Add the axis buttons to the list of items to check only once every 50 ms.

src/Input/input.cxx

@@ -727,6 +727,7 @@ FGInput::_update_joystick (double dt)
       }
      
                                 // do we have to emulate axis buttons?
+      if (_last_dt > 0.05) {
         if (a.low.bindings[modifiers].size())
           _update_button(_joystick_bindings[i].axes[j].low,
                          modifiers,
@@ -738,6 +739,7 @@ FGInput::_update_joystick (double dt)
                          modifiers,
                          axis_values[j] > a.high_threshold,
                          -1, -1);
+      }
     }
 
                                 // Fire bindings for the buttons.