Shears with efficiency 2 or higher cannot insta mine glow lichen

How to reproduce:

 

1: Place/find glow lichen

2: Have a shear with the enchantment efficiency 2 or higher.

3: Mine the glow lichen with the shear.

 

Observed Results:

The shear doesn't insta mine glow lichen with efficiency 2 or higher.

 

Expected Results:

Shears should insta mine glow lichen.