Hi dude! I just want to drop a little something I think might be useful. If you are new to console rendering, as I like to call it, don't worry it's very simple. Here's what I suggest : Open a SI Command Prompt. There, type this :
xsi -r -scene "full:path/to/scene.scn" -pass "name-of-pass" (optional, dont put it if you only have 1 pass) -verbose 3 (this option might cost you a few cpu cycles, but it's crutial for the kind of weirdness you're encountering; it will inform you of what's going on, from pre-processing to each segment rendering!)
So there you go, I hope this helps you. Type this before you go to bed, and check the logged verbose when you get back, it should inform you properly. I hope this helped!
Sincerly,