1. Hands that fuse or multiply
Cause: hands are small, high-detail and usually in motion. Fix: crop them out, or choose a source where hands rest against the body or an object. Reducing the detail the model must invent solves this faster than any setting.
2. Faces that drift
Cause: the face occupies too few pixels, or the motion moves it through changing light. Fix: tighter crop, lower-magnitude template, and consistent lighting between the two halves of the frame.
3. Backgrounds that boil
Cause: the model re-decides fine background detail every frame. Fix: choose a plain background or a static camera. Patterned wallpaper, foliage and bookshelves are the worst offenders.
4. Motion that smears
Cause: more movement requested than the clip length can resolve. Fix: one action per shot, and a longer render only after the short version reads cleanly.
5. Colour that pops or shifts
Cause: mixed colour temperature in the source, or aggressive neon. Fix: a source with one dominant light source. Mixed lighting gives the model two competing white-balance targets.
Every artefact has an input fix. Settings are the last thing to change, not the first.