Color Slider in Manual Denoise Module in Lightroom Classic v15.1 is always set to 0 instead of 25

[HpW]

The Color Slider in the Manual Denoise Module in my Lightroom Classic v15.1  (and some Versions before too) is always set to 0 instead of the "Default" of 25, even when i apply Denoise!?
So what is the official correct Setting i should use? Always on 0 or 25?
I observed the following Behaviour on Photos: if the Slider is set to 0 and i apply Denoise, some of the Colors get more Saturated, if set to 25 the Colours stay more or less the same as without Denoise.....
In some earlier Versions of Lightroom Classic the Color Slider also jumped automatically to 25 when Denoise was applied, but this doesnt happen, it always stays at 0..
Is this a Bug or what?
Here is an example of what i mean, on a Heavy cropped and 100% Zoomed in, and because of that not so great Image Quality Resolution wise:
There are some strange violet Colours, see the violet Markings, but also some more saturated Brown Yellow colours on the Deers, Orange Markings,  when set to 0  ( Left Side Image) 
The blue Marking is the little Flower which is blue violet at0, but on the Original with 25 nearly colorless....
with 25 (Right Side Image) overall the Colours stay the same as on the Image without applied Denoise
So what is the official "right" setting now???

Couldnt upload the Image here because it didnt uploaded to the end after several trys, so i had to use an external Upload Solution: https://ibb.co/B2x3n97L

[Jim Wilde]

AFAIK, the Color slider default value on import is 25 for Raw files (0 for Jpegs), and I'm pretty sure that it's been that way for a long time. Using Denoise on the raw files resets the Color slider to 0 as well as the Luminance slider it that was previously adjusted prior to enabling Denoise.

[Per Berntsen]

The Luminance slider is set to 0, and the Color slider is set to 25.

This is the default, and always has been, so this is normal.

As for your questions about the colors in the image – impossible to tell from the screenshot.

Please export the image as DNG (this will include all your edits), then upload the DNG to Dropbox or some other file sharing service and post the link here.

[Conrad_C]

Your link shows that the file is .ARW, a Sony raw file, shot at ISO 4000. Based on your screen shot, this is how I think the Color noise reduction amount is expected to work:

On import:

For raw files, I think Adobe defaults to 25.

If you applied a custom import preset in the Import dialog box, that can override Adobe default values. 

On Denoise:

All noise reduction values are reset to 0.

This is because AI Denoise addresses both luminance and color noise. The result of applying Denoise sometimes means the image now needs no additional manual noise reduction. 

But if you already adjusted the Denoise value and still see noise issues, you can then adjust Manual Noise Reduction values. 

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@HpW wrote:

There are some strange violet Colours, see the violet Markings, but also some more saturated Brown Yellow colours on the Deers, Orange Markings,  when set to 0  ( Left Side Image) 
The blue Marking is the little Flower which is blue violet at0, but on the Original with 25 nearly colorless....
with 25 (Right Side Image) overall the Colours stay the same as on the Image without applied Denoise

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If there are large patches of unwanted colors, try increasing the Color noise reduction Smoothness (Glättung) value. 

The base Color value is for small speckles of color noise such as individual pixels. Smoothness is better at addressing larger/low-frequency areas of color noise that can appear at high ISO speed values.

[HpW]

Ok, thanks for your answers so far, i tried that out with the Color noise reduction Smoothness (Glättung) value.

On this specific Image, (which is a bit a problematic one) it only does something visible when the Color Slider is set to 25, to get rid of that strange Violet Color parts.....  if setting the Color Slider lower than 25, the Smoothness Slider does not change much...

I also checked the Original ARW file behaviour, and indeed the Color Slider is set to 25 before using Denoise, then it jumps back to 0... If set to 0 without Denoise the same saturated Colors appear as on the Denoised Version

So then it is meant like this: the Denoise feature should do anything at the same time, normal Denoise and Color Denoise.....but then if necessary, still have to apply manual Color Noise Reduction, especially with such difficult Images....

I tell you its sometimes difficult to find the Right Colors for any Image, especially when you do longer sessions with many different Images, you can go somewhat "Colorblind" at times......