PVS-Studio warning V519 for webrtc

static void UpdateMetrics(AecCore* aec)
{
  ....
  dtmp = 10 * (float)log10(aec->nearlevel.averagelevel /
      (2 * aec->nlpoutlevel.averagelevel) + 1e-10f);
  dtmp2 = 10 * (float)log10(echo / suppressedEcho + 1e-10f);

  dtmp = dtmp2;
  ....
}

This suspicious code was found in webrtc project by PVS-Studio static code analyzer.
Warning message is:
V519 The 'dtmp' variable is assigned values twice successively. Perhaps this is a mistake. Check lines: 1636, 1640. aec_core.c 1640

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/