QString::setNum to convert a double into QString fails.

When converting a double into QString using QString::setNum, the return value is wrong in release mode:

Below is a code snippet to reproduce with. Notice that this certain incident is only reproducible in some machines.

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
double _val = 375648293208.0;
QString s;
QString _amessage = s.setNum( _val, 'e', 15);
printf(_amessage.toLatin1().constData());
return 0;
}

in DEBUG _amessage contains : 3.756482932080000e+11 -> correct
in RELEASE _amessage contains : 3.75648293207:000e+11 -> not correct

If tested with 375648293209.0 or 375648293207.0 or 375648293208.1 it's correct in REALEASE and DEBUG.
(Qt version used is installed from from "qt-win-commercial-4.8.0-vs2010.exe")