After the audio commentary in this post about the Farr 40 Worlds Protest, Sailkarma has a video of the final day. In the first quarter of the footage I think this incident was partly caught on film.
You can see JF tack in front of BM, completing her tack inside the zone. We can't see what happened before or that any hails were made. I think BM completed her tack and then luffed to avoid JF, which means that JF broke rule 18.3.
That is however not what the Jury decided. Here is their decision.
Do we need cameras at the windward mark?