Attack indicator doesn't indicate (most of the time) that breaking instantly-mineable blocks resets your attack

To Re-produce:

1. Summon a few chickens and give yourself a stone axe. Observe that chickens are one-hit kills.
2. Break some tall grass blocks one at a time and see that the attack indicator only shows up sometimes.
3. Break a piece of tall grass and immediately hit a chicken. Despite your attack indicator not resetting most of the time, the chicken will take another axe swing to kill and the 'weak hit' sound is played.

This goes for all instantly-mineable blocks (I tested them all), including:

• tall grass

• double tall grass

• fern

• double tall fern

• red flower

• yellow flower

• sunflower

• peony

• lilac

• rose bush

• dead bush

• TNT

• slime block

• redstone dust

• redstone repeater

• redstone comparator

• redstone torch

• torch