PVS-Studio warning V501 for OpenMS

std::vector<std::pair<std::string, long>> spectra_offsets;
std::vector<std::pair<std::string, long>> chromatograms_offsets;

template <typename MapType>
void MzMLHandler<MapType>::writeFooter_(std::ostream& os)
{
  ....
  int indexlists;
  if (spectra_offsets.empty() && spectra_offsets.empty() )
  {
    indexlists = 0;
  }
  else if (!spectra_offsets.empty() && !spectra_offsets.empty())
  {
    indexlists = 2;
  }
  else
  {
    indexlists = 1;
  }
  ....
}

This suspicious code was found in OpenMS project by PVS-Studio static code analyzer.
Warning message is:
V501 There are identical sub-expressions 'spectra_offsets.empty()' to the left and to the right of the '&&' operator. mzmlhandler.h 5288

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/