Qt Designer: Date/Time Edit value changes every time after saving when a non-default time zone is set

1. Launch Qt Designer, new create a widget.
2. Drag a Date/Time Edit, set its timeSpec to UTC. (The time zone settings on my computer is UTC+08:00)
3. Set a arbitrary date and time. (e.g. 2019/7/29 8:00:00)
4. Save the widget as ui file.
5. Close the ui file and re-open it.
6. The date and time shows in Date/Time Edit is 2019/7/29 0:00:00, which is 8 hours earlier.

Repeat step 4 to step 6, the Date/Time Edit always shows a time of 8 hours earlier.

And the content in the ui file(xml format) does change everytime.