Request with Invalid key still return the content and rate limit stepped down into No Key Limit

Question

For example

http://api.stackoverflow.com/0.8/stats?key=TEST1234&type=jsontext

Request with Invalid key still return the content and rate limit stepped down into No Key Limit

X-Ratelimit-Current 290
X-Ratelimit-Max 300

Even If I change key to another invalid key, its still continue to decrement X-Ratelimit-Current

But this getting started page says

Requests with invalid or revoked keys are not completed, they are not stepped down to the No Key limit.

Edit: Fixed!

Answer 1

Now, requesting with invalid API key returns following

{
  "error": {
    "code": 4000,
    "message": "The 'key' query parameter containing your application's public key is missing or invalid."
  }
}

So, it has been fixed now!

Answer 2

I can confirm that this indeed works even with the wrong key.

And furthermore, it seems that any request with an invalid ID is being completed.

• http://api.stackoverflow.com/0.8/users?key=test1234&type=jsontext
• http://api.stackoverflow.com/0.8/questions?key=test1234&type=jsontext

Definitely a bug. For sure.