PVS-Studio warning V557 for Wolf

void RB_CalcColorFromOneMinusEntity(unsigned char *dstColors) {
  ...
  unsigned char invModulate[3];
  ...
  invModulate[0] = 255 - backEnd.currentEntity->e.shaderRGBA[0];
  invModulate[1] = 255 - backEnd.currentEntity->e.shaderRGBA[1];
  invModulate[2] = 255 - backEnd.currentEntity->e.shaderRGBA[2];
  // this trashes alpha, but the AGEN block fixes it
  invModulate[3] = 255 - backEnd.currentEntity->e.shaderRGBA[3];
  ...
}

The same error can be found in Quake 3.

This suspicious code was found in Wolf project by PVS-Studio static code analyzer.
Warning message is:
V557 Array overrun is possible. The '3' index is pointing beyond array bound. renderer tr_shade_calc.c 679

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/