Hello,
I've been using Krita for some days, and still work on getting used to it, I'd like to say it's a wonderful software !

My problem is, I'm training at coloring under a line art, so I'm using many layers, and for one of these layers, I can't select the color (beige), instead, the advanced color selector goes in the yellow, and it's not even put on my drawing tool, like I've had selected an empty space.
I precise that I'm on the good layer when picking the color, and nothing is selected.
I've installed a bundle of brushes from David Revoy too, could it have anything to do with it ?

I've looked for solutions but didn't find much about this, I hope someone will be able to help me, meanwhile I'll keep looking, and come back if I find out what was my issue.

Can you say which version of Krita and which operating system you are using?
Were you using the Colour Selector Tool from the Toolbox or were you pressing and holding the Cntrl key to get the colour picker tool?
Was the Colour Selector Tool working properly until this problem happened?
Did the problem persist after you restarted Krita?
Installing bundles of any kind will have no effect on the colour selection tools.

If you're using the Colour Selector Tool from the Toolbox, then select the Tool Options docker and check the settings in there. If it is set to Current Layer then try it set to Sample All Visible Layers and, of course, the Update current colour box ticked.

Also, try using the colour picker tool instead to see if that works correctly. The colour picker tool shows an on-screen colour patch that updates as you click to select a new colour.

If none of that works, please post a screenshot showing your Layers docker and the Tool Options docker while the problem is happening.

It turns out I was using it from the Toolbox, and just had to use the Cntrl + Clic to get my color (I didn't know about this one), thanks, you're my savior, I was completely stuck because of this