An essential sound's ducking for ambient doesn't make sense. When I increase sensitivity, it works completely differently.

I selected a few clips as ambient, and now I want to use the ducking feature in Premiere Pro. 

And I am talking against dialogue. As you can see, there is a huge pause between dialogue. 

Doubtful in this moment should be boost of audio, but it works only in the moment when sensitivity is high when I lower sensitivity it's works random. The moment when the audio should get quiet , there is no keyframes from ducking and it is creating key frames in random places.

You can see clearly that in video I attached to this post.

The ducking should work like it works in music tab. When there's no dialogue because I'm ducking against dialogue, you should work normal and when dialogue appears audio should get quieter.