Hello,
Best way to explain is to show 
Don't know why this happen. I checked geometry was fine. I triangulated it but it didn't help.
So I fixed by combining mesh with other object.
Also I would like to ask few questions.
First is where can I found the announcement of the new build? Like today I downloaded windows installer just out of curiosity and it turns out that it's new build 2.4.205. Would be nice to know that new build is out and whats new and whats fixed.
Second is, I don't know if it is known issue, but prorender settings is not saves when I save the file. All changes what I did in render settings is gone when I open files again.
Also still I can't find the portals anywhere, may be better do not mention features which is still not implemented in user guide. Like sun/sky, etc. It's a bit confusing.
I know you guys busy with developing and you have my appreciation for that. Still would be great if you could answer a bit faster. Thank you.
Here you go
I exported to fbx so just import it to the new scene in hit render to see.
What about other things in my second message?
