If the player starts mining a block with a tool enchanted with Efficiency (either the correct tool for said block or not) and switches to a tool not enchanted with Efficiency (only the correct tool for said block works here), the game will occasionally briefly apply the mining efficiency bonus of the enchantment on the tool that doesn't have it.

How to reproduce:

1. Place a block of stone.
2. Give yourself a shovel or axe enchanted with Efficiency (level 5 preferably, since it makes it easier to notice the issue).
3. Give yourself an unenchanted wooden pickaxe.
4. Keep both your tools in your hotbar.
5. Start mining the block of stone with your shovel or axe.
6. Quickly switch to your wooden pickaxe.
   → There is a chance that you will manage to mine the block really fast with the unenchanted wooden pickaxe.

Expected result:

The Efficiency enchantment would not apply on a tool that doesn't have the enchantment.

Observed result:

The Efficiency enchantment can sometimes apply on a tool that doesn't have the enchantment.

Relates to MC-28289 MC-154881 MC-187015