I was playing and decided to go into the spectator to see a nether fortress. As I was flying around the fortress was glitching and disappearing every time I moved.

What I expected to happen was...:
I thought it would be just like normal, where you could see through blocks and see the inside of the fortress

What actually happened was...:
The fortress was disappearing and glitched out, which wasn't suppose to happen.

Steps to Reproduce:
1. Go to nether and locate nether fortress
2. Go to spectator mode and start flying around inside
3. Notice how the chunks keep glitching out and stuff