Thanks for your help. I actually solved the issue by removing vr gaze, and was able to force chrome on the pixel device to recognise my device as daydream. Even after re-attaching 'vr gaze', the pixel device now recognises itself as daydream rather than cardboard.
I had kept google canary on my pixel recognised as cardboard (for testing sake), and even after your update, it still enters cardboard.
In the past, I've also tried deleting cookies and reinstalling the browser, but neither works.
As you've said, this seems more of a browser issue rather than a Playcanvas issue.
Thanks again for your help!