training Tesseract OCR - mfr training - Segmentation fault and unable to read shape table

Question

I am training a custom tesseract ocr on a custom font and I got the .box and .tr files from the original .png files 0-20. This is the command I am running in cygwin on Windows 11.

 mftraining -F font_properties -U unicharset -O own.unicharset eng.roboto_mono.exp0.tr eng.roboto_mono.exp1.tr eng.roboto_mono.exp2.tr eng.roboto_mono.exp3.tr eng.roboto_mono.exp4.tr eng.roboto_mono.exp5.tr eng.roboto_mono.exp6.tr eng.roboto_mono.exp7.tr eng.roboto_mono.exp8.tr eng.roboto_mono.exp9.tr eng.roboto_mono.exp10.tr eng.roboto_mono.exp11.tr eng.roboto_mono.exp12.tr eng.roboto_mono.exp13.tr eng.roboto_mono.exp14.tr eng.roboto_mono.exp15.tr eng.roboto_mono.exp16.tr eng.roboto_mono.exp17.tr eng.roboto_mono.exp18.tr eng.roboto_mono.exp19.tr eng.roboto_mono.exp20.tr

This is the message I am receiving. I don't understand where / when the shape table was ever created and what the segmentation fault is.

Error: Failed to read shape table shapetable
Reading eng.roboto_mono.exp0.tr ...
Reading eng.roboto_mono.exp1.tr ...
Reading eng.roboto_mono.exp2.tr ...
Reading eng.roboto_mono.exp3.tr ...
Reading eng.roboto_mono.exp4.tr ...
Reading eng.roboto_mono.exp5.tr ...
Reading eng.roboto_mono.exp6.tr ...
Reading eng.roboto_mono.exp7.tr ...
Reading eng.roboto_mono.exp8.tr ...
Reading eng.roboto_mono.exp9.tr ...
Reading eng.roboto_mono.exp10.tr ...
Reading eng.roboto_mono.exp11.tr ...
Reading eng.roboto_mono.exp12.tr ...
Reading eng.roboto_mono.exp13.tr ...
Reading eng.roboto_mono.exp14.tr ...
Reading eng.roboto_mono.exp15.tr ...
Reading eng.roboto_mono.exp16.tr ...
Reading eng.roboto_mono.exp17.tr ...
Reading eng.roboto_mono.exp18.tr ...
Reading eng.roboto_mono.exp19.tr ...
Reading eng.roboto_mono.exp20.tr ...
Flat shape table summary: Number of shapes = 15 max unichars = 1 number with multiple unichars = 0
Segmentation fault