Weird bug: Assertion failed: stream->newRatePosition != newSampleRate (For multiple pitch changes first and only for specific text at specific pitch)

[sssee123]

Seems I'm not the only one with this problem:
#39

I will do Pitch 1 and the results are as expected:

I will do Pitch -1 this time and the console will show me: Assertion failed: stream->newRatePosition != newSampleRate

I will do Pitch -1 again and change only one letter of a word and its fine again:

I generated the voice file over 10 times each, every time the same output.
For this fail to recreate I have to make several pitch changes first, and it only works for certain texts at certain pitches, which is weird.