It looks like this post has not been resolved. To answer your question, differences between realtime and your final rendered image may be due to your render settings or it could also just be a bug. Below you will find a few suggestions to try to fix this:
1. KeyShot realtime uses a render method similar to Maximum Samples. Please make sure to use the Maximum Samples quality setting under Render > Render > Options.
2. If this is a bug, then you can try resetting any glitches in the scene lighting by importing the scene into a blank KeyShot file.
Click *Import* or *File > Import*
Browse to your BIP and click *Open*
Select "Import Scene" and confirm your import
If the issue persists, you can check the following variables: the material type, the hdr environment, the lighting method (Product or Interior, Performance or Basic).