The bug is... 

 The pillager did not notice the villager through iron doors even though he was withing seeing range. There were windows in the door so the pillager can see him. also with a zombie he just path finds the villager by going around the door. Pillager didn't, it looked like he didn't even notice the villager! The villager did not act worried either.

In the video. the pillager just looks at me. it is as if it didn't notice the villager through iron doors. I had to make the video short but later when I broke the iron door the pillager shot the villager. But they stayed like they were in the video for 2 more minuets and I went all around the villager and he didn't care.

How to recreate.

• Do the set up I did in the video. might need to pause...
• Spawn a pillager a couple blocks away facing the door. ask if you need to...
• Watch what happens.
• Pretty much pause the video and recreate exactly what happened.

What I thought would happen.

The pillager would path find around the door and kill the villager.

What actually happened.

The pillager did not notice the villager and vise versa. Instead they just look at me and at a cow nearby.

Side notes.
No mods or texture packs or seeds or anything, only normal Minecraft how it comes from Mojang.