Line art doesn't take sequencer scene override camera into account when computing line results, now it will try to get override camera info from render and use that camera if line art override camera itself isn't set. This will however not fix VSE preview line art result, since the preview render doesn't give actual camera object, but rather uses a set of clip planes and matrix info, thus it's probably not possible to do preview camera override under current architecture. Pull Request: https://projects.blender.org/blender/blender/pulls/110287