Crazy! The same scene and the distant area on the left (second image) is noisy as heck and everything else is clean. The scene has an HDRI and there is a window over there, so there is plenty of light available.
got curtain at the window? if yes it will block some light…
No, no curtains there. I am swapping out the HDRi to see if that helps.
Hi glorybound, try turning off some of the VRayLightMtl lights it looks like you have in that corner. That seems like an issue from one of those.
Are render elements active, they usually a good source of information where the noise comes from.