I have an HP Envy X360 15,6" OLED and the latest version of Windows 10 Pro with all the latest stable updates, as well as the latest version of Designer.
I have a problem with Designer displaying incorrect RGB values, which don'y agree with their corresponding CMYK values.
For example, the red values used in the gradients in the attached file are:
R: 204 G: 34 B: 40
C: 0 M: 100 Y: 100 K: 0
However, when I click on any red stop, I cat an incorrect RGB value of R
When converting CMYK to RGB the document's colour profile is used for the conversion to give a more accurate colour value that is within the gamut of that profile. As PaulMc has said most web based converters don't take any consideration of colour profile into the conversion.
I've just taken a document in Illustrator using US Web Coated SWOP v2 with a 0,100,100,0 CMYK value and that gives me an RGB of 227, 6, 19
Doing the same in Designer again using US Web Coated SWOP v2 gives me an RGB of