Reproduction steps:
1. Open project in "project.zip"
2. Build for iOS
3. Connect a supported MFI controller to an iOS device (tested with Dualshock 4)
3. Deploy the project to the iOS device using Xcode (IMPORTANT: check note 1)
4. A square will appear in the center of the screen every time you press a button
5. Try pressing some buttons on the connected controller

Unexpected behaviour: button presses are not processed

Reproducible with: 2018.4.22f1, 2019.3.12f1, 2020.1.0a17 -> regression, 2020.2.0a9
Not reproducible with: 2017.4.40f1, 2020.1.0a16

Devices tested:
Reproducible with:
VLNQA00310 iPad Pro 12.9 (iOS 13.4.1),
Not reproducible with:
VLNQA00015, Samsung Galaxy Note8 (SM-N950W), Android 8.0.0, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540 (XboxOne controller)
AppleTV (tvOS 13.3.1)

Notes:
1. After application launches, Minimize and Maximize the application as there is an issue where the controller does not connect until the app is Minimized and Maximized 1211074
2. This issue has been backported into 2018.4, 2019.3 streams