Integration Problem with Facebook

Hi, I have a site with WordPress 3.0 (updated from 2.9.2 two weeks ago). I usually publish some news on the wall of a FaceBook page with no further problem until the 24th. of June, when it began to show some characters as if they were not UTF-8 encoded (the text in the site still works fine).

However, the database is UTF-8 encoded:
Charset: utf8
Collation: utf8_general_ci

And the PHP code in the header generates the following:

<meta http-equiv=”Content-Type” content=”text/html; charset=UTF-8″ />

Would you be so kind to tell me if something has changed from 2.9.2 to 3.0 that could this problem or if this is a FaceBook problem?

Thanks

Raúl