Ice Camera sequencer

[aio]

Hello forum,
I've been trying to implement a way to visualize cameras edits inside the viewport using ice.
The master camera is stuck to the other shots through a pset. The shots cameras are put in a group/array and a shot index is picking through them.

But randomly i've got strange bugs, the lights start to behave weird. They don't cast shadow properly or the point lights have have a limited range only a small region is lit.
I don't know what's causing this and this problem pop up sometimes in production. The only solution is to reimport the camera model containing all the shots.

Could someone have a look at the ice tree and tell if i've done something severely wrong? Or if there's a cleaner way to achieve that?
This kind of setup is really useful for previz etc. I know you can get a similar result using the mixer but it's not as flexible.

Thank you.

the cameras model with the compound inside and a scene. (S2012)
http://dl.free.fr/fBWzLU2HU
http://dl.free.fr/o2KH0UHz4