PVS-Studio warning V517 for TrueCrypt

BOOL CALLBACK PageDialogProc(....)
{
  ...
  else if (nCurPageNo == HIDDEN_VOL_HOST_PRE_CIPHER_PAGE)
  ...
  else if (nCurPageNo == HIDDEN_VOL_HOST_PRE_CIPHER_PAGE)
  ...
}

This suspicious code was found in TrueCrypt project by PVS-Studio static code analyzer.
Warning message is:
V517 The use of 'if (A) {...} else if (A) {...}' pattern was detected. There is a probability of logical error presence. Check lines: 7477, 7523. Format tcformat.c 7477

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/