Hello @Dean Tang,
It's worth noting that the injected input is sent to the desktop of the session where the injection process is running. We're not in a position to know whether
InjectTouchInput blocks the I2C channel or not but there is another driver sample HIDInjector you can check.
As this issue is complex, please open an incident at link below so that our engineer can work with you closely: https://developer.microsoft.com/en-us/windows/support/?tabs=Contact-us and please choose the 'Desktop app UI development - Windows controls and common dialogs' for Windows SDK for this issue. In-addition, if the support engineer determines that the issue is the result of a bug the service request will be a no-charge case and you won't be charged.