a zombie was targeting me while in creative

So I was in creative mode and I was testing out local difficulty levels by making a zombie grinder, and when I finished killing a bunch of zombies, I noticed one that naturally spawned 20 blocks away and it was agroed onto me. I confirmed this by walking around it and it was continuously following me with its arms up. Although I don't know why this zombie in particular was agroed because I couldn't replicate this issue.