QDir breaks windows 8.3 paths in long paths strings

I have a path in a QString : \\?\C:\Users\OLIVIE~1.BAR\ONEDRI~1\DOCUME~2
SOE643~1

This was constructed from a normal path, prefixed by
\\\\?
, then passed to GetShortPathNameW (to be able to get the 8.3 version of a path longer than MAX_PATH)

That Path, pasted in the windows explorer, is valid. Note how the 8.3 format is different than in regular paths, (folder SoilPolutionxxx should have been named something like SOILPO~3.)

But then i do:

QDir dir(path);
dir.setFilter(QDir::NoDotAndDotDot | QDir::Hidden | QDir::Dirs);
entries = dir.entryInfoList();
for (int i = 0, n = entries.count(); i < n; ++i)
{
  const QFileInfo& entry = entries.at(i);
  QString subdir = entry.absoluteFilePath();
  ....

and subdir is now C:\Users\OLIVIE~1.BAR\ONEDRI~1\DOCUME~2\SOE643~1 (i guess something removes the \\?\ when path is not long?). Which is now an invalid path