PVS-Studio warning V576 for peerblock

#define PB_BLDSTR "PeerBlock " STRINGIFY(PB_VER_MAJOR) "." \
        STRINGIFY(PB_VER_MINOR) "+" " (r" \
        STRINGIFY(PB_VER_BUILDNUM) ") - DEV BUILD"

int WINAPI _tWinMain(....)
{
  ...
  TCHAR buf[64];
  swprintf_s(buf, sizeof(buf)/2, L"%S", PB_BLDSTR);
  ...
}

This suspicious code was found in peerblock project by PVS-Studio static code analyzer.
Warning message is:
V576 Incorrect format. Consider checking the fourth actual argument of the 'swprintf_s' function. The pointer to string of wchar_t type symbols is expected. peerblock pb.cpp 153

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/