IPR different to final render result

[stezza]

Hi folks.

I have an issue where I use IPR to get my transparent plastic looking just how I want it but when I go to render - the result is very different.

Any ideas as to why this would be?
VRay latest release.

[yolov]

Looks like GI to me, but that's just guessing. Would it be possible to send the scene over, so we can take a look?
One difference between IPR and production rendering is that IPR will always use Brute Force + Brute Force for GI (primary and secondary), no matter what is specified in the settings. But the image on the right looks like it has GI disabled altogether (if it's GI, of course).

Btw, is this CPU IPR, or GPU IPR? And is it compared to GPU or CPU production rendering?
In any case, being able to test the scene locally will make it a lot easier to identify the problem.