When the output switches to rabbit the picture actually resembles a rabbit. I am unsure if this experiment was supposed to be a “haha look how stupid AI is” type thing or not, but it seems like the cloud vision api is performing as intended.
Since human would do the same error, I think it's kind of a praise of how close to human is the AI.
Depending on orientation our first interpretation is also either a duck or a rabbit, because our vision is obviously biased to interpret things in the orientation they are most likely to occur based on our priors that have evolved in the presence of "up" and "down" directions. The AI correctly takes the orientation into account because it also matters in its priors, having been fed training data that captures those human priors.
Now, most computer vision algorithms do strive for some degree of rotation (and translation etc) invariance, because a classifier that gets confused when you rotate the input by 15 degrees or whatever isn't very useful in the real world. But complete rotation invariance would just be a case of Artificial Stupidity in an application that attempts to classify like a human would. Input orientation is meaningful information.