Sorry for not replying to this, I must have missed it.
We do have a couple of scene where we can reproduce this behaviour. I would ask if it is possible for you to send through your scene so that we can investigate it more. Instructions on how to send the scene to us can be found in my signature.
I’d also recommend to update to v6 HF1, the daily build you are using is quite old and most likely many of the bugs in it will have been fixed in the v6 release.
Cheers,
Rowan