Eyedropper tool (Illustrator) only picks up white.

An ongoing problem in Illustrator in some files and I'm not sure what the cause of the issue is:

When I attempt to select color using the eye-dropper tool in some Illustrator documents, the color picker only picks up white. I have to take a screenshot and then paste that back into the document as a bitmap for the color picker to work properly. I have tried using the SHIFT-key and I did check the double click options, all looks good. The document color space is CMYK.

My personal opinon on the eye dropper: I only use it for transfering font styles or colors - I never use any of the other features. Font style transfer seems to work OK, but color transfer has been a problem as long as I can remember (except right after it was introduced, it did work flawlessly for a while). 

BTW: I can't post the Illustrator version, as this is so hidden that I just gave up searching for it. I have the newest update. It used to be straighforward to get the version number, just click on Help and find the version number. When I click system info in "Help" now, I get the AUTOCAD versions??? Some things in cc have become pretty ridiculous...