FFmpeg/React video editor renders successfully but ignores object recolor and color grading

I built a custom AI video editing app using:

- React

- TypeScript

- Vite

- FFmpeg

- SAM2 segmentation/tracking

- Replicate API

Problem:

The app successfully renders/export videos, but object recolor and cinematic color grading are ignored in the final export.

What works:

- UI updates

- object selection works

- render pipeline starts

- export completes

- masks/tracking appear connected

What fails:

- final exported video keeps original colors

- targeted object recolor does not appear

- FFmpeg render finishes but output video looks unchanged

Current suspicion:

The edited frames or FFmpeg filter chain are being bypassed before final encode/export, and the pipeline may still be exporting the original source video.

I need help tracing:

- frontend state to backend render

- FFmpeg filter chain

- compositing path

- where edited frames are lost

- whether the final export uses original frames instead of processed frames

Has anyone seen this happen in a React + FFmpeg + AI mask pipeline?