Win 10, R19.053 Studio, Corna Beta 1 Release
Load the scene and render, there you are: artefacts.
Well, the only appear if you use a sky with really, really low settings, but when playing with a situation only lit by candles (and when I wanted to add a bit fading skylight) I stumbled across them.
The sky's intensity is 0.001, with a brighter sky the artefacts won't appear. It does not matter either if I use an intensity of 1 and REALLY lower the color values in a Rawa-Fake sky or if I use a Corona Light material with an HDRI where I really lower exposure or intensity - the artefacts will come over you.
Just saying.
CU
Michael, trying to break things