What does view interpolation stop working if I generate twice?

[ForMyCat]

These are the input images:

I am able to get the following result after I click generate the first time after I run "python gradio_app_interp_and_loop.py".
https://github.com/user-attachments/assets/c9c4df01-2ebe-4e4a-9ca0-b61498d735e5

But when I click generate again it shows black screen result:
https://github.com/user-attachments/assets/a39ca6c4-f251-4699-a851-a0890aaa4224

I have to kill the python process and run a new one to make it work. Any idea of what may be causing this? I am running on a Ubuntu machine with 4090 24G.