QTemporaryDir creates 256 directories, yet isValid() returns false

On Android, QTemporaryDir may create 256 directories for certain paths, yet isValid() returns false and path() returns empty string.

This works correctly on Windows, but not on Android:

QTemporaryDir temp(QStandardPaths::writableLocation(QStandardPaths::DownloadLocation) + "/");

EXPECTED: Either QTemporaryDir creates one directory, isValid() returns true and path() returns correct path, OR no directories are created, isValid() false etc.
ACTUAL: QTemporaryDir may work correctly, or it creates 256 directories, isValid() returns false and path() returns empty.

I suspect that QFileSystemEngine::setPermissions() call in q_mkdtemp() (qtemporarydir.cpp:127) fails for some reason, so the loop keeps creating new directories.