/* make sure we are not seeking in corrupted stream */
if (this_frame_sample < lower_bound_sample) {
  decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
  return false;
}

ends up with a weird value for this_frame_sample from somewhere..

/* make sure we are not seeking in corrupted stream */
if (this_frame_sample < lower_bound_sample) {
  decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
  this_frame_sample = upper_bound_sample;
}

allows the CHD to still decode fine