The short version:
This isn't a "Half-winged" bird, this plane is missing the entire left wing. Previous versions of AH had Macchis in 1/2 wing and full wing missing options.
Perhaps, but it is specific to 1.04 and I'll explain why:
In previous versions, you could lose half a Macchi wing, as well as the whole thing. When you lost half, it took all the work in the world to wrestle that guy down. When the whole thing went, goodbye!
Now, it may be that with 1.04 they've removed the "half wing" graphics and what I'm seeing is the result.
But look closely: when I hold the plane wing level, I lose alt at a dangerous rate; when I go knife edge, I'm able to climb. I was hit at 500 feet. At one point I got it to 8k.