Steps to repro:
1. Open attached project
2. Make sure in Build Settings "Script Debugging" is enabled
3. Build for iOS and deploy the Xcode project to the iOS device
4. Try to tap on the screen

Expected: TouchControl.tap count should increase
Actual: TouchControl.tap count stays at 0

Reproduced in: 2019.2.13f1, 2019.3.0b12, 2020.1.0a14

Note: Not tested in 2018.4, 2017.2 as Input System was officially introduced in 2019.1

Devices reproduced on:
iPhone X (iOS 13.0)
iPhone X (iOS 12.0)
iPhone1 1 (iOS 13.0)
VLNQA00272, Samsung Galaxy S10+ (SM-G975U), Android 9, CPU: Snapdragon 855 SM8150, GPU: Adreno (TM) 640