The attack indicator shows up when facing an invisible entity

The attack indicator (the cooldown bar under the cross of the center of the screen) shows up if facing an invisible mob or player

One expects it not to, since, you know, it defeats the purpose of being invisible

Yet it does

Steps to Reproduce:
1. Make a mob or a player invisible
2. Face it with a sword or an axe or a tool in hand (attacking is NOT required)
3. Notice the attack indicator