If the iPhone Launch Screen is set to 'None' in the Player Settings when the application is built and run on an iPhone XS Max the PointerEventData.delta X and Y components in IDragHandler.OnDrag will always be multiples of 3. This is very unhelpful as it means the smallest possible drag will always have a magnitude of 3 instead of 1 which makes drag controls very jerky and imprecise

To reproduce:

1. Download attached project "drag-test.zip" and open in Unity
2. Open "drag-test-scene" scene
3. Go to Player Settings and set iPhone Launch Screen is set to None
4. Build for iOS
5. Deploy the Xcode project to iPhone XS Max
6. Drag across the screen

Expected results: Observe the X and Y components of the PointerEventData.delta in OnDrag printed out in the middle of the screen and these are multiples of 1
Actual results: Observe the X and Y components of the PointerEventData.delta in OnDrag printed out in the middle of the screen and these are always multiples of 3

Notes:
- On iPhone XR it seems that values multiples of 2
- Could not check on Unity 2018.3.0a7, 2018.3.0b6 and 2019.1.0a6 because Build crashes on launch
- Stacktrace is shared in Comments section

Tested with:
- iPhone 7s Plus iOS 12.0 - Not Reproduced
- iPhone X iOS 12.1 - Not Reproduced
- iPhone XS iOS 12.1 - Not Reproduced
- iPhone XR iOS 12.0 - Reproduced
- iPhone XS Max iOS 12.0 - Reproduced

Reproduced on Unity 2017.4.0f1, 2017.4.13f1, 2018.1.9f2, 2018.2.13f1 and 2018.3.0a6