This came out of code review for JDK-8289115:

I attempted to test this with the sample app in JDK-8249737 and Microsoft.Windows.Simulator using the simulator's "Basic touch mode".
https://stackoverflow.com/questions/40274660/windows-10-how-do-i-test-touch-events-without-a-touchscreen

The "Too many touch points reported" exception seems to be thrown consistently with
const bool isDirect = true; (original before #394)
and const bool isDirect = (ti->dwFlags & TOUCHEVENTF_PEN) == 0; (this PR)

I didn't see the exception with const bool isDirect = IsTouchEvent(); (#394)
and const bool isDirect = false (which is probably what IsTouchEvent() returns here).

Not sure what this simulator actually sends, but someone more knowledgeable might want to have a look at what's happening.