How to reproduce

1) Put yourself in /gamemode creative.
2) Hold a sword in your hand. (which prevents you from breaking blocks)

3) Hit a block whilst moving. When flying fast and holding down left click it's very noticeable that your movement is getting frozen.

This likely has to do with the fix for https://bugs.mojang.com/browse/MC-156013 freezing players, but when the block breaking is cancelled on the server side the client is not notified correctly.

Alternative Method:

1) Go on a server with spawn-protection enabled.

2) Break a block in the spawn protected region whilst not an operator. You shouldn't be able to break any blocks.

3) (optional) Put yourself in /gamemode creative. (makes the issue clearer)

4) Start walking whilst attempting to break blocks around you, you'll notice movement keeps getting frozen.