[GO] objects turn white

Having a small problem on the GO. Sometimes, objects turn totally white on the GO - see pic / movie. It only happens on the GO, not on Rift or desktop.

In several projects, I notice objects sometimes turn white when loading the streaming level a second time. Most of the time only the trees, sometimes everything on the streaming level.
The trees are on the persistent level, streaming levels have a lighting scenario.

Anyone a clue what could trigger this and how to fix it?

Small movie here