Ground plane not working on Android w/ Pixel XL

I am trying to implement the ground plane feature on iOS and Android at the same time. That's why I want to use Vuforia.
The feature works fine on iOS but doesn't seems to work at all on my Pixel XL (1st gen).
The positional tracking just doesn't work, and no planes gets detected. Objects stay at a fixed distance from the camera instead of staying in place when I move around.

Tested on Pixel XL (1st gen)
Android 8.1.0 Security Patch 5 March 2018
Tested many Unity versions from 2017.3.1f1 up to 2018.1.0b10
Latest Vuforia used: 7.1.27
iMac running MacOS 10.13.4 Beta (17E160e)

I see quite a lot of people complaining about that online like in these threads:
https://forum.unity.com/threads/vuf...racking-on-google-pixel-or-samsung-s7.513938/
https://forum.unity.com/threads/ground-plane-augmentation-drifting-or-jittering.516863/
They seem to have the exact same issue.

The answer to their thread wasn't helpful for me. I spent quite a while tying to map different rooms with different lighting conditions with no success.
Looking at the IKEA Catalogue app on that same device, I don't know if they used Vuforia, but they seem to have the same issue. Leading me to think, it might be a feature that once worked but has been broken with an OS update.
I tested the Vuforia Ground Plane sample on the asset store, same issue.

This seems to be a quite terrible bug so I suspect you're aware of it and most likely already trying to solve it.
Considering the latest Unity beta still has this bug, I am concerned about when you're planning on releasing a fix.

I would really appreciate any info on whether or not you're planning on fixing it, and if yes, what's your expectation on when you'll be able to do so. It'd be good if you could at least tell me if we're talking about weeks or months.
That would allow me to know if we can rely on Vuforia for our project or if we'll need to take another approach.

Thank you very much.

 

Anyone?
I'm still testing every week the new Unity beta (currently 2018.1.0b11 w/ Vuforia 7.1.27) and still not working even with the sample package.

 

I guess this could be the explanation:
https://developer.vuforia.com/forum/ground-plane/how-know-if-fusion-using-arcorearkit#comment-63165

Looks like at the moment Vuforia Fusion doesn't leverage on ARCore. This means that even on a Pixel Ground Plane will only "work" with the Vuforia implementation and apparently it's "not there yet".

I also agree that it would be good to have an ETA of some sort on the proper ARCore implementation, at least to know if we can expect it with Unity 2018.1 (announced for Spring...).

 

It is probably related indeed, but not less mysterious for me. The list of Ground Plane Supported Devices includes the Pixel and the S7. And there is a sample package that doesn't even work!
I don't quite get what's going on but it feels like it's been working for a while but no longer does...

 

Lack of positional tracking is often the result of poor detail or lighting in the environment you are testing in. Can you share screenshots of the area you are testing in and/or test in another environment and see if you get better results? Spending additional time scanning the environment will also help improve the experience.