MOUSE_MOVE event dispatching not consistent

Case:
1.stage.displayState = StageDisplayState.FULLSCREEN_INTERACTIVE

2.stage.mouseLock = true

3.using alternativa3d as content

4.60fps

5.Windows desktop AIR

Delta time from last event in onMouseMove, result in <17ms(60fps), but sometimes it become >32ms, arround 2-5 times in one second.

1.EnterFrame is always <20fps when problem occur

2.When MOUSE_DOWN, PROBLEM GONE! then MOUSE_UP, problem back.

MOUSE_MOVE event delta time always representing in 1-3 times, like 16-17ms, 32-34ms, 49-52ms

When I "drag" my mouse(with mouseDown) instead of just move, sum of movementX significant increased.

This inspired me seems some mouseMove event are not dispatched.

How is AIR handle mouseMove? !