First, I believe that you are correct and that the issue is connected to the performance release. I see that when I bypass the new release, the correct count displays. However…
I suggest that you try enabling the “Fetch after the page loads” option:
That might cause the dataset and the page to get things done in the correct order. Give it a try and let me know as soon as you can if it helps.
Seems to me that the issue is in fact a bug, but I’d like to see what affect the load option has so I can give QA as much information as possible regarding the problem.