PVS-Studio warning V595 for Quake3

void FloodPortals_r (node_t *node, int dist)
{
  ...
  if (node->occupied)
    Error("FloodPortals_r: node already occupied\n");
  if (!node)
  {
    Error("FloodPortals_r: NULL node\n");
  }
  ...
}

This suspicious code was found in Quake3 project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'node' pointer was utilized before it was verified against nullptr. Check lines: 769, 770. bspc portals.c 769

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/