Bug Custom Device values not updating while focus lost

Whenever the game play window loses focus, myDevice.control.ReadValue() always returns the same value. I get this both in the Editor whenever I click on the Inspector Window and in Standalone Windows Runtime whenever another program has focus. This is also shown in the Editor in the Input Debugger, which only updates values on the Custom Device window when the Game tab has focus (no events are shown if focus is lost), although the Mouse Device window will still show Events

Input System 1.3.0
PlayerSettings: RunInBackground selected
Input System Settings : Update Mode --- Process In Fixed Update
Input System Settings : Background Behavior --- Ignore Focus
Input System Settings : Play Mode Input Behavior --- All Device Input Always goes to Game View
Custom Device Layout: canRunInBackground = true
(Device/layout set up following https://docs.unity3d.com/Packages/com.unity.inputsystem@1.3/manual/HID.html)

Changing Background Behavior to either Reset & Disable option doesn't help..

I've attempted to upload an inputtrace showing constant event updates except when focus is lost, however as I always get an OverflowException when reloading these I don't know if it is readable or not.