When starting to mine a random block next to tall grass and then switching to a tall grass block will do the following:
1. it will instantly destroy the tall grass and play the sound (fine until here)
2. it will immediately play the breaking grass sound again!
3. when continuing to hold down the mouse button will attempt to break the dirt block under it, but when the breaking animation completes it just plays the breaking tall grass sound again and the breaking animation starts again (when continuing it will then normally destroy that dirtblock)