The bug

Breaking Frosted Ice (from the Frost Walker (I/II) enchantment) with a Diamond Pickaxe enchanted with Efficiency V is far too slow. However, normal Ice breaks normally.

To reproduce

1. Obtain a diamond pickaxe without enchantments
2. Switch to Survival mode

3. /setblock ~ ~-1 ~ frosted_ice

4. Take note of how long it takes to break the frosted ice with the diamond pickaxe
5. Enchant the pickaxe with Efficiency

6. /setblock ~ ~-1 ~ frosted_ice

7. Take note of how long it takes to break the frosted ice with the enchanted pickaxe

Observed behavior

There is no difference in breaking time using the enchanted pickaxe and the pickaxe without enchantments.

Expected behavior

Using the pickaxe enchanted with Efficiency would result in a smaller breaking time of the frosted ice.