일부 페이지에서 S3에 저장된 에셋을 사용하는 커스텀 이모지가 CDN을 사용하지 않음

So it does. If I actually post, the emoji is shown correctly in it.

If the fix for the retort plugin is similar to how the admin area would be fixed, I could maybe give it a shot trying to fix the plugin as the custom reaction emojis are quite widely used on my discourse instance.