Cycles: Denoising generates artifact(s)
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System Information
Linux Ubuntu 16.04
Nvidia GeForce GTX 970

Blender Version
Broken: 2.79-RC2
Worked: not available (denoising is new)

Short description of error
When using denoising feature an artifact is generated. The object is a simple glass body. The denoising parameters are on defaults.
The scene gets rendered correctly without denoising (see images)

Exact steps for others to reproduce the error
Based on an attached .blend file with minimum amount of steps

without denoising

with denoising

red circle: here is the artifact



I could reproduce this on 2.79 RC2, but it works OK (no artifact with denoise on) using Blender 2.79.1 hash 11a9434 (Sun Sep 10 03:08:03 2017) from "Download Latest Builds".

Bastien Montagne (mont29) triaged this task as "Normal" priority.

@Lukas Stockner (lukasstockner97) I guess you'll know whether this was already fixed or not? If yes, can you please also check commit is in 2.79 branch? Thanks

Maybe new Russian Roulette method helped here?
Just to mention just in case. If you increase Lamp size (1 for example), some weird things still happen in this scene using resent blender from buildbot: