Did you try using scalable settings, many high end settings are not supported on mobile (or will produce odd results like this). Also, have you tried using static lighting (and building static lighting)?
First question I have: How is it working in the Editor?
Did you try to change the Lighting asset to Static/Movable?
When I had this issue, I played with the Static and Movable parameters for the assets and then rebuild lighting.
If I recall correct, in my case, I changed it all to Movable and the lighting issue was fixed.