Social.ReportProgress() can only use once per achviment for iOS GameCenter?

I used the following code to write the achivments from Game Cente.

Social.ReportProgress("myAchivementID", 2.5f, (bool success) => {
   // handle success or failure
   Debug.Log("ReportProgress: " + success);

The first try, I saw it successed by the callback, and I actually saw it show 2 percent degree on the Game Center Achiviment UI.
But after any try, it always failed, and I saw the callback show “Already reported myAchivementID”.
How could it be? If it’s once-for-used per achivment?
I need your help, thanks !!

You can’t report the same progress for an achievement more than once.

It might give the same message if you report less progress as well, but you will have to confirm that since I can’t remember for sure…

I had the same issue, I was able to report progress once and then all further calls failed. This was happening to me because, like your code snippet, I was reporting progress as a float. Progress must be reported as a double.