first of all sorry for my bad english. There are two scenes with the same render settings, models. The only difference is the background and the light intensity. Once the scene is mapped, the difference is huge, absolutely huge. I do not know this is a bug or something I did wrong.
In the scene there are only standard cameras, the right render messed up also with IR and QMC too. The example shows the results with the Physical Renderer. Thank you for the answers.