synth_plugin.show_editor() IndexError: basic_string

[0xdevalias]

I load a VST3 (Serum), change some patch settings, then save the patch, and I get the following crash from pedalboard:

Traceback (most recent call last):
  File "/Users/devalias/dev/0xdevalias/poc-audio-pedalboard/./synth_vst_loader.py", line 131, in <module>
    synth_plugin.show_editor()
IndexError: basic_string