Why I am I getting this output from copy dialog box?

Question

I was copying my old Windows files to a new partition for unnamed reasons and then the copy dialog box gave me this screen :

I had 0 items remaining but 45 seconds and 1.83GB left to copy.

After a few minutes Windows presented me this :

According to windows, there is no files remaining, the speed is 0 bytes/s and there is 0 bytes left.

Now, this might not be unusual if the copying finished just then. But, it was copying all sorts of files and took about 15 minutes to complete the copy. It stayed at the same screen above only that the names of the filenames were flashing by.

Is there any valid reason for this or should I be posting this in the Windows Bug Forum or something?

I'm running the latest version of Windows 10 (I'm not an insider though).