I was looking at my armor stand and I went inside it (You stand in it) and I found Z-fighting in the head and in the top line (what the head and arms are on). NOTE: I couldn't get any good pictures of the armor stand Z-fighting but you can reproduce it by:
1. Go inside of armor stand
2. look at the head and "side lines" (the ones that make up the body almost)
3. Z-fighting is there