API key limit does work and exceed the quota

Today I found abnormal usage in my account. I try to limit the quota and delete the API key. But it keeps increasing until 806.26 and even exceeds my quota limit which is 790.00. Do you have any idea why?

Yes. The system is slow and the user stats lag, causing this issue.

You can try dropping your limit down to $770 and see if that gets you closer to $790 during laggy days.