Reproduction steps:
1. Print or open "QRCode.jpg" in a device different from the one you will be testing
2. Open customer's attached project in "arfoundation-samples.zip"
3. Build the project for iOS and Deploy it to an iOS device
4. Select Image Tracking and allow Camera access if prompted
5. View/film the QR image with the Camera (on a piece of paper or phone)
6. Once the image is tracked a Game Object with the same image will be created above it
7. Place some Cubes directly on the QR code by tapping the Screen
8. Move the Camera around the QR and inspect the QR code's position

Expected result: QR code will not be seen because it is covered by cubes
Actual result: most of the time QR is really high in the vertical axis and is above the cubes

Reproducible with: AR Foundation 4.1.0-preview.6 (2019.4.7f1, 2020.2.0a20)
Could not test with 2018.4 because could not resolve package related errors

Devices tested (reproducible):
VLNQA00310 iPad Pro 12.9 1st gen (iOS 13.4.1)
OnePlus A5000, Android 10, Adreno 540, Snapdragon 835

Notes:
1. Some images are attached
2. A good way to notice where the image is placed to quickly change the camera's position