Confusing error when ghostscript isn't installed (Bug #899)

Automatic data capture from a valid PDF, fails with the attached message box and the following console output:

$ result/bin/auto-multiple-choice gui
Command failed at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Basic.pm line 212, <GEN1378> line 3.
terminate called after throwing an instance of 'cv::Exception'
  what():  OpenCV(4.7.0) /build/source/modules/imgproc/src/smooth.dispatch.cpp:617: error: (-215:Assertion failed) !_src.empty() in function 'GaussianBlur'

Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Use of uninitialized value in sprintf at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Boite.pm line 210.
Warning: unable to close filehandle GEN1377 properly: Broken pipe at /nix/store/92rqszv638bbakpfg95gb9f09gkngwf8-auto-multiple-choice-1.6.0/share/perl5/AMC/Subprocess.pm line 115 during global destruction.

This is AMC 1.6.0 on NixOS. The console outputs suggests the issue is with OpenCV (version on nixos is 4.7.0), but the _src.empty() failed assertion suggests that maybe the problem happens earlier. The scans/ subdir remains empty, so maybe it's a graphicsmagick issue?

I'm the maintainer of the NixOS package, so there's no help to be found downstream. I'm interested in any suggestion as to how to start investigating this issue!

Thanks,
Best regards,
Thibault