Colors don't match
The color picker rounds the CMYK to the nearest whole number but the color window does not. They should be made consistent.
There is a larger request about it: https://illustrator.uservoice.com/forums/333657/suggestions/32532658
It does not mention the color values, but feels relevant enough.
For some having these decimal spaced is crucial. For some — irritating. And for some — the current approach is the only way to get both at the same time :)
So I don’t really see a clear way to solve this. A way to customize decimal spaces is nice, but then it will require to have both the panel and the dialog to be mentioned, to maintain the current way it works... anyway, thanks for noticing and reporting.