I'm under the same impression, and, that if the conveyor belt stops, the X-ray stops at the same time automatically. AFAIK, X-ray scanner is like a scanner as the name suggests, not like a video camera.
Red color in final positive print strongly points towards light leak, I'm afraid. The X-ray damage is more neutral in color. Light leaks are usually red if they strike the film from the back side, exposing the bottom red-sensitive layer. Still, I wouldn't rule the x-ray completely out. Please show examples if you can scan your images!