Very frustrating issue indeed!
I prepare cmyk and spot swatch files for print and never use RBG.
Suddenly today my files have partially and randomly changed to rgb from the cmyk I had set.
I've resorted to using Illustrator 2020 for now.

I posted this workaround in another thread...

Make your colour swatch a global (tick the box) - This is keeping my colours stable

It would be much better if Adobe just FIXED THIS ****! Stop being a **** Adobe

I too am being driven nuts by this. What is the point of painstakingly building palettes only to have to check them again every time I open a file. When I import colors from a saved palette into another document it often (but not always!) asks whether I want to merge or add because colors of the same name have become different.

It renders this otherwise fabulous program inappropriate as a professional tool. I have neither the time nor the inclination to recreate colors all day long.

PLEASE FIX THIS BUG.

does anyone colour change when moving an object. Like I sample a colour from something and its a muted version of the colour. Then when I move the object it becomes the correct colour I sampled. when I release it reverts back to the muted colour

Same issue. what kind of a joke is this.
Like if i have to fight with the program for the colour i like.
Well, within a minute it changed it again by itself.

Same issue as the others.
Colors slightly change at very low increments when i leave a file open.
Till suddenly i notice or a client notices when i export files. Im not copying and pasting from CMYK to RGB.
My color setting are square. Ive actually had someone from Adobe reinstall my color drive.
Been happening for the past year+. Unfortunately i dont really have the time to keep sleuthing so i just keep popping up to see if anyone has found a solution.
Down to try something else if there are ideas.

https://community.adobe.com/t5/illustrator/illustrator-randomly-changing-my-file-s-colours-while-file-is-open/td-p/10113279

Same issue. Trying Affinity now. I am so so so DONE with this :-/

Im so over this issue... continues to happen and even gets worse.
20years on Ai this has never been an issue, but now it is.
Please dont tel me its my colour profile or I might explode.

FUKN FIX THIS ADOBE!!!!!

No, colour change only happens in Ai

Im seeing very noticeable changes happening more quickly now too... It seems to affect light and dark colours more dramatically.

Yes its not acceptable to have a major problem like this exist in Ai, especially as you pay top dollar for it.

Ive contacted Adobe directly and posted comments here and other places.. yet Adobe ignore this issue.

I'm now just adapting and getting used to having to adjust ALL COLOURS in Ai documents before exporting finished art - So frerakin annoying!!!!!

Do you see this slight color change anywhere else? Example; I'm working on adjusting colors on a CMYK document to get them as close as possible to a separate RGB document. We use a third party color picker to get the color value off the original RGB, and then when we put that into Illustrator CMYK, AI then displays a noticeably different color (not the typical RGB -> CMYK shift) and different number color values. We've spent hours going over the color profiles within AI and matching them between all the programs and other management settings that might be contributing. We only see this inconsistency with AI, very frustrating to type in a CMYK value, and then have it change it the values. We now have to sit and play the toggle game on the palette sliders to correct it. I'm willing to be told I'm totally missing something, but colors changing unexpectedly is a major problem for software like this...

Looks very frustrating :( Does it happen in one particular file only or across several docs?
Have you tried to move one colored to a different file and see how it behaves there?
Does it occur in new docs too?
Can you share the file for everybody and the team to test?

Also - I'm not copy pasting between CMYK / RGB files.

This colour change is happening to elements that never leave the file / colour profile they were created in.

Hi Jotham

Yes, Ive never seen this happen before either - 20+ years using Adobe

Yes, colours change live while working on a file. I tested this by checking a colour breakdown.. continued to design in the file without closing.. then going back to check colour breakdown about 30 mins later. So weird.

To add to this - Working on a file, save close. reopen file and work, colours change again, save close. Ive had elements sitting off to the side of a document that I havnt touched in weeks/months and you can see a massive change over time to the colours of these elements. Its like every time I open the file the colours change slightly, and aginf the next open, and again.. till its radically diferent. See attached img, this element has been sitting on the side of my document for the last 6 weeks, look at the change in colour.

I've never seen this happen in a live file without copying or changing color modes, so I'm actually curious to how this happening to you while only working on a live file. Does this happen if you make the color a swatch or is it only when you pick a from the color picker?

Just a guess as to what might be happening. I noticed you are working in RGB and CMYK color spaces between documents. If you happen to switch between RGB and CMYK documents it will change the color values as CMYK has a smaller color gamut. Meaning if you select an RGB value and then switch to a CMYK document or copy to it then it will convert it to CMYK values within its gamut as it can't technically show those RGB values in CMYK.