Light Leak - more info?

Hey guys,

Can I get some more info about how and why light leaks happen, other than from overly thin walls?

I have some floors that are a simple plane, and so I get why the leaks appear there.  However, my walls are half a meter thick, and I'm experiencing light leaks.

Does it happen when objects intersect?

Note, I visit Sansar in desktop mode.  I'm not sure if light leaks also happen in VR mode.  Please advise if you can.