Hi Vuforia Team,
We got a Jitter Problem with iPhone XS / XS Max and iPad Pro (2019) but it works with iPhone X/ XR, iPad Air2 / Pro(2017). (Unity 2018.4.9f1 LTS and Vuforia 8.1.10 built with xcode 10 and 11.2beta)
We tested the same Stuff with 2019.2 / Vuforia 8.5.8 and Xcode 11 and it worked well with your Assetstore Demo Scene but not out of the box clean Unity 2019.2 Scene
So my Question would be if there is a specific Vuforia Version where these Devices work, or is it a Unity 2018 Problem and if you have any Advices regarding the new iOS Devices.