SoundTouch library messes up the ending when pitch-shifting - c++

Question

I'm using the SoundTouch library to pitch-shift some audio files. Everything works well, except the last few hundred milliseconds of the new audio file are not like the original file. Here is the original file:
And here's what I get after pitch-shifting:
As you can see the ending is not right. It's like there was nothing there in the original file, when there certainly is.
Here's the code I'm using:
int generateFile(WavInFile *file, SoundTouch *st, string fileName, int semitones)
{
const bool speech = true;
SAMPLETYPE samples[BUFF_SIZE];
WavOutFile *out = new WavOutFile(fileName.c_str(), (int)file->getSampleRate(), (int)file->getNumBits(), (int)file->getNumChannels());
int nChannels = (int)file->getNumChannels();
assert(nChannels > 0);
int num, nSamples;
int buffSizeSamples = BUFF_SIZE / nChannels;
st->setSampleRate((int)file->getSampleRate());
st->setChannels(nChannels);
st->setPitchSemiTones(semitones);
if (!speech)
{
st->setSetting(SETTING_USE_QUICKSEEK, 0);
st->setSetting(SETTING_USE_AA_FILTER, 0);
}
else
{
st->setSetting(SETTING_USE_QUICKSEEK, 0);
st->setSetting(SETTING_SEQUENCE_MS, 40);
st->setSetting(SETTING_SEEKWINDOW_MS, 15);
st->setSetting(SETTING_OVERLAP_MS, 8);
}
while (file->eof() == 0)
{
num = file->read(samples, BUFF_SIZE);
nSamples = num / (int)file->getNumChannels();
st->putSamples(samples, nSamples);
do
{
nSamples = st->receiveSamples(samples, buffSizeSamples);
out->write(samples, nSamples * nChannels);
} while (nSamples != 0);
}
st->flush();
do
{
nSamples = st->receiveSamples(samples, buffSizeSamples);
out->write(samples, nSamples * nChannels);
} while (nSamples != 0);
delete out;
return 0;
}
And yes, I delete WavInFile *file later in my code. So my question is- Why is SoundTouch doing this and how can I fix it?
Also I cannot simply cut the wrong part of the new audio file because I'm generating hundreds of files this way so cutting every single one of them would be...