Hex code changes from illustrator to another

My friend made a CMYK document, its colour profile is the same as mine (u.s web coated swop v2)
she makes a colour with hexcode 8FA177 and then she sends me the ai file and I open it in my pc with the same document settings, but then the hexcode changes to 8ea177 

There are five colours, out of which 3 have this issue.  Is anyone else facing this? and is there a fix? 
How can one know which is the correct hex code