Linux - Crash when Square waveform is selected

[crshrprt]

OS: Linux
Distro: Debian Sid
Host: Carla 2.5.8 or BespokeSynth nightly

Qsynthi crashes when a Square waveform is selected in Wave settings or Potential setting.

I was able to get the following error message on crash, using carla-single:

terminate called after throwing an instance of 'std::runtime_error'
  what():  Pairing error: list sizes differ

It happens in both the binary release from https://qsynthi.com/ or a self compiled one from this repo.