Heavy distortion when enabling 96khz

[ruenes1]

I'm not sure if this is a bug or a problem on my side so I prefer to open a discussion here rather than a code-related issue.

I'm using a Pi zero 2-based mt32-pi on a MiSTer (official build) with the latest mt32-pi version. The MiSTer is configured to output 96khz audio, which works fine when connecting the optical output to a external dac: the dac acknowledges the 96khz signal and reproduces the audio correctly.

When using the mt32-pi with the standard settings (48khz samplerate), everything works fine. However, if I enable the 96khz sample rate with the following settings:

sample_rate = 96000
chunk_size = 512

Any audio coming from the mt32-pi (either in mt32 or in fluidsynth mode) is heavily distorted: all sounds are just high pitched white noise. It tried to enable the overclock settings for the Pi zero in the config.txt file but this didn't changed anything. Changing the chunk size didn't seemed to produce any difference. Sounds coming from the MiSTer play fine and the DAC still reports a 96khz sample rate. Could it be a problem with the bit stream format from the mt32-pi?