PVS-Studio warning V501 for Lugaru

int Game::DrawGLScene(void)
{
  ...
  if(freeze||winfreeze||(mainmenu&&gameon)||
     (!gameon&&gamestarted)||(mainmenu&&gameon)||
     (!gameon&&gamestarted)||(!gameon&&gamestarted))
  {
    multiplier=tempmult;
  }
  ...
}

This suspicious code was found in Lugaru project by PVS-Studio static code analyzer.
Warning message is:
V501 There are identical sub-expressions '(mainmenu && gameon)' to the left and to the right of the '||' operator. Lugaru gamedraw.cpp 2237

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/