Contacts have been damaged

Most of my contacts have been corrupted with the strings "X-EVOLUTION-FILE-AS:" or "X-APPLE-OL-EMAIL1-LABEL:" been added to the email adress.

I have an Iphone and use a MS Outlook. All contacts are synced via the icloud.

On the icloud the contacts do not have an email adress anymore - but they do on the iphone and on Outlook, however thousands of them with these strings attached.

What can I do?

Thank you for your suggestions.

O.