Chrome Version       : 62.0.3202.75
Mac OS 10.12.6 (16G29)

What steps will reproduce the problem?
(1) Connect a device using window.navigator.requestDevice
(2) Set listener on 'ongattserverdisconnected'
(3) Plug in a USB Bluetooth adapter
(4) Wait a few seconds
(5) Unplug USB Bluetooth adapter
(6) Notice that your 'ongattserverdisconnected' has been called.

What is the expected result?
I would expect my device to remain connected.

What happens instead?
My device is disconnected

Please provide any additional information below. Attach a screenshot if
possible.

In my setup, I set the color of my device when it connects.  In this case, when the 'ongattserverdisconnected' is called and I can clearly see that device.gatt.connected is false, my device remains the color that I set it to.  The device only goes back to its original state when I refresh the window.  This seems to indicate that a connection is still open with the device, even though in the javascript it appears to be disconnected.

I've also noticed this similar behavior:
(1) Load web page
(2) Insert USB Bluetooth adapter
(3) Call window.navigator.requestDevice, then call device.connect()
(4) Notice that device.connect() never resolves.

Seems like plugging in/unplugging a USB Bluetooth adapter causes all sorts of issues.  Let me know if you need any logs.