Question: Instance Normalization with track_running_stats= True

Hi,
I have noticed that the Generator uses "track_running_stats= True". Is there a particular reason for it? From what I can understand when the track_running_stats is True it acts as a BatchNormalization layer but I am not sure. Also, I have noticed that the new StarGAN has a track_running_stats= False. Is this some kind of a bug or what?

Would be grateful for any clarification,
Best Regards