I have my Mac (El Capitan) account as before setup with Exchange to my SM.latest Enterprise edition. Using the Mac Contacts app I created a new contact, checked "Company" and entered phones, work address, and some notes. After clicking done much of the info such as all address but zip was gone, company not saved, etc. I checked via web mail and the same.
I unchecked "Contacts" from the exchange account in Mac Prefs and added CardDAV which appears to be working better.
As reported before I also saw with EWS that carriage returns were stripped in the Card notes so if I entered multiple line breaks/paragraphs once clicking DONE they were all removed.