PVS-Studio warning V501 for VirtualBox

QString UIWizardExportApp::uri(bool fWithFile) const
{
  ....
  case SunCloud:
  {
    ...
    QString uri("SunCloud://");
    ....
    if (!field("username").toString().isEmpty() ||  //<==
        !field("username").toString().isEmpty())    //<==
      uri = QString("%1@").arg(uri);
    ....
  }
  case S3:
  {
    QString uri("S3://");
    ....
    if (!field("username").toString().isEmpty() ||
        !field("password").toString().isEmpty())
      uri = QString("%1@").arg(uri);
    ....
  }
  ....
}

This suspicious code was found in VirtualBox project by PVS-Studio static code analyzer.
Warning message is:
V501 There are identical sub-expressions '!field("username").toString().isEmpty()' to the left and to the right of the '||' operator. uiwizardexportapp.cpp 177

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/