hit a block with a sword using the Modifier "attackspeed" movement stops

Hello, 

i found a bug. If you hit the block with any sword, that has the Modifier "attackspeed" at about 40 or more you can not move in any direction for a few ms. But if you are doing it really fast by using a Speedclicker at around 40 clicks per second the movement and even the gravity stops working. This bug works only in creative mode. I'll send a video showing the bug with and without speedclicker.

 https://youtu.be/12TpDLOSEcY