Mobs can see invisible drowned

The bug

When drowned mobs are invisible, other mobs like snow/iron golems can still instantly see and attack them as if they weren't invisible.

How to reproduce

1. Build a setup like this

2. Spawn a drowned in one of the slots
3. Splash it with an invisibility potion
4. Spawn a snow golem in the other slot

Expected behavior
Snow golem should do nothing

Observed behavior
Snow golem attacks the drowned. This does not happen with any other hostile mob.