Windows 10 Touching Outside Modal Dialog Causes Unhandled 10th Touch Later

Question

-- latest on Apr 12th --

I have found a easier way to reproduce the problem and realized there is a pattern, I also updated my code to reproduce it. Basically any outside the modal message box tap was not properly handled, which will cause a delayed non-response after 10 additional taps. Please see all the details in:
https://github.com/GuangSunshine/WpfTouchTest/blob/main/README.md

I also created a feedback using the Microsoft Feedback Hub app: https://aka.ms/AAbwiuw

-- original question, you may skip --

Hi I am creating some WPF based application on Windows 10, with a touch screen.

I found the following will cause the touch screen become unresponsive for a while:

1. From my main window, click "Button 1" to pop up a modal message box (System.Windows.MessageBox.Show(this, "simple MessageBox", "test", MessageBoxButton.OKCancel); ). When this message box showing, tap quickly and repeatedly on the main window, this will cause the pop up message box to blink, then tap the "Close" button to close the message box.
2. Now tap any button on the main window, the button turns blue, which means it gets the focus, but the button is not clicked. Keep on taping the same button, it takes another 10 taps to click the button.
3. It looks to me that when I tap quickly and repeatedly on the main window (outside the modal message box), the touch events becomes backed up, or maybe it becomes a multi-finger touch or some other events, these events back up; the system might think there are 10 fingers on the screen now (my touch screen supports 10 touch points); then in the subsequent non-responsive touches, it clears the 10 fingers, so on the 11th touch, it comes back to normal and promoted the touch event to a mouse click event.
4. Using mouse will not show this problem.

Any one has a good explanation on this? Is this a bug, or a feature? The reason I am investigating this is my actual application sometimes become unresponsive to touch for a while, then after a few try (not necessarily 10 taps), it becomes normal again. Very annoying.

Please see the simple code demonstrating this problem in https://github.com/GuangSunshine/WpfTouchTest.git

(Edited on Apr 09)
I found another case to show this problem:

1. From my main window, click "Button 1" to pop up a modal message box.
2. While this pop up message box showing, tap outside it on the main window once, it blinks and make sound, this is expected.
3. Wait until the blink and sound effect finishes. Now tap the outside of message box again, to make it blink again.
4. Wait, tap again to make it blink again. Remember we tapped outside 3 times, made it blink 3 times.
5. Now click "OK" on the message box to close the message box.
6. On the main window, click "button 1" again.
7. On the pop up message box, click "OK" to close it.
8. Repeat step 6 and 7 two more times. Now we have tapped "Button 1" 3 times since step 5.
9. Now click the "Button 1" for the fourth time, you will find tapping the "Button 1" has no response, if you try 2 more times, it is back to normal again.

Looks to me that once you tap outside a modal box for more than once, it somehow memorizes the number of the additional taps, and later "punish" the user by not responding to user's tap for that many times. Seems this "punishment" is capped at 10. Very interesting.