Negative "updates" count after clearing all Thread

Just letting you know that the "X updates" counter at the top of the page has a small glitch.

In this case I had two updates from the Tumball game. After clicking the "Clear all updates" button, it told me that there are -4 updates.
Screenshot:

After logging out and back in, the counter is now back at 0.

This glitch seems like nothing serious.