Artifacts with HDR2SDR function

My TV does not support HDR/BT.2020 so I use the HDR2SDR function on my N2 (set to active in CE-settings).
There are heavy artifacts if HDR2SDR is enabled, see example at time 0min:08sec (top left corner, sky).

The artifacts are not present if HDR2SDR is disabled.

This function is provided on an as-is basis and is not something that we intend to modify as the tone mapping is a complicated part of the kernel.

The HDR2SDR behaviour is the same with the old 3.14 kernel and the NEW 4.9 kernel on N2 (to dark, no bright colors, artifacts). @TheCoolest mentioned, tonemapping is a CE-thing (Problem with tonemapping HDR-to-SDR mapping on N2) , not a Kodi issue, so I hoped with the NEW kernel HDR2SDR will improveā€¦
And as otherwise mentioned, with the old 3.14 kernel on S905X, HDR tonemapping is better (not to dark, better colours, no artifacts).
It would be great, if the status of HDR2SDR with CoreELEC-NG (and the NEW kernel 4.9) is the same as on S905X with the 3.14 kernel.
Any hope?