RGB colour values change when copying an object from Illustrator to Indesign

Oh, I just realized that you are not the same commenter as the OP. You have the opposite settings. Either way, they should be harmonized with the synchronized Color Settings and both files be the same color model between the two applications. Generally, File>Place; don't drag n drop.

Since your Illustrator file is set to RGB; so should your Edit > Transparency Blend Space be RGB  for InDesign. Web intent is not the main thing.

For InDesign, what is Edit > Transparency Blend Space set to? RGB right?

I'm seeing this same thing happen also in CMYK colour space.
I'm copying an object from Illustrator with swatch specs C=38 M=70 Y=88 K=40 to Indesign and when pasted in InDesign the colour swatch has changed to C=39 M=79 Y=89 K=41).
Same colour spaces/profiles. While the difference is minimal, it IS present.

Both Illustrator and InDesign are latest versions 2025, run on Win 10.

Hi @Daniel24299474wzlh , The Color Settings or assigned profiles might affect the appearance of the pasted RGB values, but shouldn’t affect the values themselves—there’s no color conversion when you paste an RGB object.

I can’t replicate your problem in CC2021, so it could be a bug. Have you tried resetting your caches and prefs in both apps?

RGB 245|97|74 in Illustrator with ProPhoto assigned:

Pasted into InDesign with sRGB assigned I get a mismatched appearance, but the values match:

Synching the color settings in Bridge doesn't mean that the color spaces assigned in the documents cannot be changed after creation nor would it affect any existing files. It only sets up the default conditions for new work.

Check the profiles actually assigned to each file.

Normally you should not copy & paste. Save ai ai and place it in InDesign. 

Do both, the ai file and the indd have the some color profile?