Some meshes renders as black at HTML build

Hello.

We are currently working on a HTML 5 project. We solved many problem and send countless bug reports so far but right now we are experiencing a problem we have no idea why.
We get some reports from our test users that some meshes renders as black.

The two wing like pillars are identical meshes using same materials but espacially at macbooks some of them rendering as black.

I really dont know why. Same mesh, same mats but it is some times black and some times rendered correctly.

Hey Terena,

It almost seems like it is losing its direct lighting information, but it is going to be hard for me to troubleshoot this issue without the project in front of me and some more context as to how the lighting in the scene is set up.

Would you be able to provide me with a test project where this issue is occurring?

To clarify, I do not need the executable, but rather the project itself. Simply include the Content, Config, and .Uproject files/folders in a zipped folder attached to your response.

If you have further questions please let me know.

Cheers,

We finally solved the issue. It seems that some drivers at mac os yosemite caused the problem. Macbook airs and pros using El Capitan renders meshes without problem. My guess is Display Adapter drivers for Yosemite is the problem.