My first inclination: K-9's are usually well trained, but the officer was not in uniform.
It will be interesting to see how this comes out.
My guess is that the K-9 officer inadvertently triggered his remote door release, something that is normally used in an emergency. He dog responded the way he was trained. Remote door release=hostile situation.
In my 35 years raising and Dobermanns, experience has shown it is almost always the human in the wrong.
The dog wouldn’t care about a uniform, the odd part is how he got out of the car, that doesn’t make sense to me.