Hitting an entity during its invincibility frames still causes tool durability to diminish.

When hitting an entity, even if it doesn’t take damage (due to not being a mob, or having invincibility frames active), the player’s held item loses durability (if it can lose durability). For example, spam-hitting a sheep (10-12 cps) with a wooden sword will make the sword’s durability decrease significantly more than just 2-4 durability points. See the attached video for an example, where I am spam-clicking on some sheep, and the wooden sword’s durability is halved, from what should have been only 8-10 durability points.