Error with custom "traits"

[bisbisz]

Running python3 nftgen.py --project example --config config.yaml --generate-images with basic or/and original traits its succesfully, But getting an error when running python3 nftgen.py --project example --config config.yaml --generate-images with custom traits.
Traceback (most recent call last):
File "nftgen.py", line 148, in <module>
main()
File "nftgen.py", line 123, in main
su.generate_images_project(
File "/home/user/generator/src/utils.py", line 1045, in generate_images_project
generate_images_project_basic(
File "/home/user/generator/src/utils.py", line 715, in generate_images_project_basic
img.paste(layer, (0, 0), layer)
File "/home/user/generator/venv/lib/python3.8/site-packages/PIL/Image.py", line 1582, in paste
self.im.paste(im, box, mask.im)
ValueError: bad transparency mask