Error with Facebook's crossdomain file?

We are receiving some webplayer logs with crossdomain errors connecting to "https://graph.facebook.com" via a WWW object in our Facebook Canvas game.

The error is: "Policy can't be constructed from empty stream."

The code we use to connect to the FB API hasn't changed and this occurs inconsistently across our user base.

Based on the Security Sandbox documentation, it would appear as if Facebook's crossdomain.xml file is either UTF16 or missing a BOM when this occurs but since we can't reproduce this in our tests, we can't verify.

This is preventing many players from being able to access our game.

Has anyone else experienced this or happen to have a solution?

Thanks!