head not showing (if not obama)

[hg111]

When trying to train on a video with a portrait of a person different than obama, head is not showing. I have used exactly same parameters, e.g 25 fps, 512x512, 8000 frames as in obama and even similar green background

https://github.com/ashawkey/RAD-NeRF/assets/3297238/d1095e97-f482-4f3d-b3cc-2abc586375ce

Can you help please ( @ashawkey )