QWidget completely ignores setting its position before show

The attached simple CMake based test app creates a main window

 with two buttons 'Show 1' and 'Show 2'. Both buttons alternately

 show or hide two more corresponding main windows.  We set the

 second one's geometry at creation, but not the first one's.

The main windows' geometries are saved before hiding and

 recalled before showing.

Now the BUG: Notice that after manually moving the windows around,

 then upon hiding and showing by clicking the buttons, main window #1

 will NOT honor the saved position it is given no matter how many times

 it is hidden and shown, while main window #2 does.

(Notice both main windows do honor the saved size however.)

We do want Qt to go ahead and pick a full initial geometry, but

 thereafter honor our saved settings. But it won't honor the position.

It seems that it decides to stay in 'auto-placement' mode and won't

 accept any new position after that.

Please note: QSettings is not a good option for this specific part

 of our application, we need this local technique instead.

Thanks.