I was working in creative on a small project in a tundra and whilst holding top snow/layer snow, I was unable to break grass decorations, but when I switched to a different item or an empty slot I was able to break it.

Steps to Reproduce:

1. Place grass and ferns
2. Attempt to break the grass and ferns while holding a snow layer

Observed Results:
The grass and ferns cannot be broken.

Expected Results:
The grass and ferns should be able to be broken.

Video:
Minecraft 2021-07-17 09-15-39.mp4