Issue with setProgress in swift3

[oniikal3]

I tried to use setProgress(0.0, animated: true) at first but when I get progress by "self.progressBar.progress" it's return 0.3 not 0.0 and I tried to set 0.3035. It's still return 0.3 for me.
Why it's not update?

[oniikal3]

I have set at "self.progressBar.progress" instead of "setProgress" and it work fine!.
But I need animated. Is it a bug?