Rendering problem for VS Ultimate 2023?

[Airone]

Hello everyone,
this is a period in which I'm using VS much more than usual and I'm often encountering obstacles that don't allow me to carry forward my ideas. Today I encountered another obstacle that I can't overcome. I created a grid of 9 images (3x3) resizing them with the PIP Path effect. To each of them I applied the AutoSketch effect (or filter?) which progressively recomposes the image. This is the result in the Edit phase (the images are not the original ones, but the result has not changed.):

At this point I rendered to create an MP4 of the work done, but to my surprise this was the result:

Thinking it was a memory problem, I closed VS, restarted the PC and without doing anything else I re-ran the render. This time though, instead of having a screen full of 2s, the screen was full of 9s!!
I do not know what to think. Ideas?