When Qt is switching windows, stationary touch points will appear. At this time, the operation page responds with a pan gesture because there is always one touch point present.
 
The issue can be reproduced using Examples/widgets/gallery
The debug.log file in the attachment was captured based on the Examples program with debug mode enabled.

The files "正常日志.txt", "异常日志 1.txt", and "异常日志 2.txt" in the attachment are the logs captured by the event filter in my application. I attempted to resolve the issue using touch cancel, but it had no effect.