Windows: QFileDialog::getSaveFileName() repeats extension if selected filename edited (native dialog)

Using QFileDialog::getSaveFileName() with a file filter of:

"All NASA/FUN3D files (*.b8.ugrid *.mapbc);;NASA/FUN3D b8.ugrid files (*.b8.ugrid);;NASA/FUN3D mapbc files (*.mapbc);;All files (*)"

Given a destination dir containing files named junk.b8.ugrid and junk.mapbc

1. Display the QFileDialog::getSaveFileName() dialog box
2. Navigate to the given destination dir
3. Enter the file name junk (no extension) in the dialog box
4. Using mouse, select junk.b8.ugrid from the autocomplete popup
5. Left-arrow and change the file name to junkx.b8.ugrid

1. Save

1. QFileDialog::getSaveFileName() returns junkx.b8.ugrid.b8.ugrid

This may be related to QTBUG-109877

6.5.0 windows QList()
QFlags<QFileDialog::Option>()
QList("C:/dev/projects/qtbug110027/junkx.b8.ugrid.b8.ugrid")

qtbug110027.exe -n
6.5.0 windows QList(-n)
QFlags<QFileDialog::Option>(DontUseNativeDialog)
QList("C:/dev/projects/qtbug110027/junkx.b8.ugrid")