Since 14th nov the friends and followers endpoints are returning incorrect headers

[chiax]

Since yesterday i am getting
[x-warning] => Invalid OAuth credentials detected
On endpoints
http://api.twitter.com/1.1/friends/ids.json
and
http://api.twitter.com/1.1/followers/ids.json

But the weird part is the request is getting processed, i am getting response and my rate limit is getting used.
[x-rate-limit-limit] => 15
[x-rate-limit-remaining] => 9

I am not sure if there is something changed in the api overnight or is it justme with this issue.
It was troubling because, i was using that header to mark user accounts as not to check, as user might have revoked access to our app.
But this wasn’t the case. Since yesterday we got that warning from all our users.
Thank you

[episod]

We’re experimenting with an even stricter OAuth implementation. Are you performing your OAuth by query string or by auth header? Can you share the signature basestring you generate for a failed request?