strange fireflies

[artmaknev]

Any clue why this happens?
When column touches the ceiling I have those strange fireflies occur.

[johan belmans]

round corners?
Singles planes? If so add a shell modifier.

[romullus]

Does your walls has thickness?

https://coronarenderer.freshdesk.com/support/solutions/articles/5000516209-i-can-see-noise-in-the-corners-of-my-scene-

[maru]

Yup, my guess would be rounded corners or object intersecting with ceiling without thickness.

[artmaknev]

Sweet! That was easy fix!! Thanks guys! 

Surface was a plane, adding shell modifier worked indeed!