i expected that leaves blocks that you hold or are in your inventory or that are thrown on the ground would have the fast black-filled look to it. Same with breaking particle effect.

The thing listed above were looking as if it were in the Fancy setting and not the fats setting even though it was in the fast setting.

1. put setting to fast
2. get a leaf block into inventory
2a. break leaves blocks in survival
3. observe

video is kinda short, but its the best i could do when only being to upload a 10 MB video.