[pipcleo]

Thought I'd post this after wasting hours trying to debug a scene...
Not sure if its a a bug but an HDR emitter plane/standard emitter when mirrored in studio previews fine but will not render

[choo-chee]

I had a similar problem in Maya, all you need to do is reverse the normal of the mirrored plane and it will work.

[Tok_Tok]

I had the same problem, it was actually rendering right in FIRE (3ds Max) but when rendering Production the plane's face was flipped and emitting light on the other side.