I think it depends really. If subject matter is anywhere similar it's pretty close to stealing their character or painting. If you can find the color combination somewhere else then go for it. If you are literally copying the image and using the eyedropper tool to pick up the exact hex code then I'd say that the intent is wrong. Let's say you are taking light brown, cool blue, and black. No problem as long as you don't like take the exact Hex code. In that case if taking the Hex code the intent is to copy. Let's say someones character has a white chest, black body, yellow head and tail with red markings everywhere. If you were then to make a character even of another species and give it a white chest, black body, yellow head and tail, and give different markings in different places but still red in color then it'd be intent to create a copy. It's mainly intent. You can't copy the exact hex codes or color pattern without intending to make your character or art exactly like them.
For example my planet design blue grass and green sky is taken from an episode of 321 Penguins. However just swapping two colors is pretty generic and I extended upon that with swapping ocean and swamp coloring and cloud and dirt coloring. Let's say someone creates a plane blue Lion. If you were to take that and extend it to be a slightly different shade and give markings and add coloring to the mane or face and chest that is different then the original it could be done.
The key is to make it so that the artist could look at it and not think you were trying to copy it. If they think you did and don't do that over every little thing their is either a coincidence and you didn't take inspiration from it, or you copied it.
Like for example there are several oc's that took me a long time to come up with a color palette on that I liked (one that actually took over a year of playing around with the design until I really enjoyed it, the main issue being the colors)
And if I noticed someone that took their colors exactly, I'd be a little questionable as to why they just couldn't make their own palette, even if it was similar, but I wouldn't force them to change it unless they actually took features of the design itself
So it's a big ??? for me
I would never take a color palette from a design I saw because I would find it really weird to do so, but I may make a palette similar to it if I liked how the colors matched (with my own edits of c bc I like my designs being unique and I'll often finding myself in need of extra colors that are more than I intended to use as I go)
Ig that's kind of a good point, but when I use the same colors I try to make them different shades or like if the one I had seen originally used blue as a main color, I would try to use a different color as the main color
My worst sin when it comes to this is that I'll occasionally use a color palette online like from colourlovers.com or sm but lately I haven't been needing to do that bc I like coming up with my own colors