Lightroom auto-masking issue

See the remarks by WobertC

But, I will advise you of a different workflow.

First up, select the adjustment brush, return all sliders to default.

Now the differing workflow

Turn that auto mask off. Create your mask, you do not need to be neat about it. Then turn on Range Mask (at bottom of panel). Typically select color. Select the color picker (eye dropper) and click on, perhaps shift click on for multiple selections, or click drag on the  red door (or whatever area you are working on). Display the mask. At this point you may want to reclick where that eye dropper came from as to deselect it (it gears in the way if you do not, annoying). In the Range Mask tools is Amount (Smoothness if you are using Luminosity ) slider, tweak it as desired. You may want to hold down on the ALT key when doing this as to see the mask in a different way.  If you still have parts of your image contained in the mask (that you do not want in the mask) then change the edit mode, select the erase option, turn the auto mask on fir this, and erase, carefully, the offending areas.

Then alter the various sliders as you see fit.

https://m.youtube.com/watch?v=C77T5vspa9Y

https://m.youtube.com/watch?v=PSzO6JH7w7Q

https://m.youtube.com/watch?v=SFuHYJvBXIQ

https://www.digitalphotographyformoms.com/lightroom-range-mask-selections-now-more-accurate/

Do you see that little triangle just above an to the right of the slider that says [Amount]

Click on the triangle (spinner) to open and reveal all the Brush sliders.

The "Amount" mode is very useful in situations when you might adjust several sliders for the Brush (eg. Saturation + White Balance + Texture, etc). The Amount slider will then adjust ALL the sliders of the Brush together.

Also, be aware, with the Brush it is the very center + of the Brush that selects the Tone/color that you want to be affected by the Auto Mask. So if your Brush centre + passes over bright and dark tones then both these tones are painted by the brush.

Note in the video that the author does one click only on the 'global' tone he wants to adjust with automask.