Villagers can see player while on Spectator gamemode

What's happened: When I was on Spectator Gamemode, Villagers were seeing me even when I was on GM 3.

How to reproduce: 

1. Find a Villager
2. Turn Spectator gamemode
3. Approach to the Villager 

GIF Video: https://gyazo.com/deaecd0e3a0bddcb382cc43d710851d2