Hey,
i need some help!
I do not know if my file is buggy, but when it finishes rendering, the light walls will have spots. something that is not seen in the pre-vizualization.
Plz help 
I believe you need to go to your Render settings and increase ‹ Interpolation › (under Global Illumination).
Hello,
I agree the interpolation value might be the answer.
Please have a look at the following link to get more Tips and Tricks on rendering parameters:
artlantis.com/2017/10/30/speed- … antis-6-5/
Best regards,
That link is an excellent summary of tips for 6.5. The original video covers the same in more detail, but it’s hard to refer to when you want to check something. More tips like this would ease a lot of frustration and questions. Good job!
Thank you !
Merry Christmas !