Steps to reproduce:
1. Create a new project
2. Install Input System package
3. Setup On Screen Controls for an Android device
4. Build to Android
5. Press the screen with 1 finger and before releasing press the screen with a second finger
6. Log TouchID's and UIElements hit, observe how the second touch is not translated into UI event line OnPointerDown

Expected results: Second touch is translated into UI Event line OnPointerDown by InputSystemUIInputModule
Actual results: Second touch is not translated into UI Event line OnPointerDown by InputSystemUIInputModule

Reproducible with according to the user: Input System 1.8.2 (2021.3.44f1)

Notes:
-According to the user the issue reproduces mostly on low end Android devices when the framerate is below 30fps
-Forum post: https://forum.unity.com/threads/input-system-1-8-2-released.1590456/#post-9908010
-A workaround for this issue is to replace the cache of control references m_PointerTouchControls with the cache of touch IDs (integers)