PVS-Studio warning V595 for Scilab

static void appendData(....)
{
  ....
  sco_data *sco = (sco_data *) * (block->work);
  int maxNumberOfPoints = sco->internal.maxNumberOfPoints;
  int numberOfPoints = sco->internal.numberOfPoints;

  if (sco != NULL && numberOfPoints >= maxNumberOfPoints)
  ....
}

This suspicious code was found in Scilab project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'sco' pointer was utilized before it was verified against nullptr. Check lines: 305, 311. canimxy3d.c 305

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/