Hi,
I have reported this problem a while ago as a few other people as well. As soon as I place to my scene 2 sky objects, one for Gi and the other for the reflection and refraction it causes bugs. I have to use two objects because otherwise the sky with intensity set to 0.8 causes too strong reflections.
This was reported a few times since the version 7. It was supposed to be solved. Any news on this issue?