UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.167 Safari/537.36

Steps to reproduce the problem:
1. Dock Pixelbook to hub which includes external monitor
2. Drag windows to external monitor
3. Undock Pixelbook from hub
4. Redock Pixelbook to hub with external monitor

What is the expected behavior?

What went wrong?
Windows do not return to external monitor, remain on Pixelbook.

Did this work before? N/A 

Chrome version: 64.0.3282.167  Channel: n/a
OS Version: OS X 10.13.3
Flash Version: 

Ignore Chrome version information as I am filing for a customer.

Peripherals - the monitor is an HP Z27s, Microsoft Natural Ergonomic Keyboard 4000 and a Razer Deathadder Elite mouse (these are plugged into an Aukey USB-c hub, and into the Pixelbook).