Proxies make IBL disappear

#1

I hope someone can help. I am on a deadline and facing a problem.

I have a large scene with a building and a lot of trees. The scene is setup with an IBL to light the scene.
The trees are made with Mental Ray proxies.

When I render an animation on my renderfarm. Each first frame a computer renders is okay and the following are not. It looks like the ibl disappears and the scene is only lit by the sun light.

When i take the trees out of the scene it renders like it should. So it looks like it has something to do with the proxies.
Everything i render in the viewport looks okay.

#2

Did you group the IBL into a new group?.. If so it will break the connection.

#3

I did group the IBL. I will try if it will help to take it out of the group.

But it renders when i delete the trees. And then the IBL is still in a group.

#4

Unfortunately that did not solve the problem.
I made a new IBL.

#5

I solved the problem.
One off the proxies seemd to be bad. I rewrote the proxy and then everything was okay.
Really strange the first frame rendered okay and the following not.