MoxiEngage gives you the option to choose which contact information to keep.
If you see the option to "Use This Version" or "Use Email Version" after editing a contact in MoxiEngage, this is because there was a difference between contact information from your email and contact information being saved in MoxiEngage.
Your MoxiEngage contacts sync with your email contacts, so MoxiEngage is asking you which version of the contact you want to save. When prompted with this message, select the option where the most recent change to the contact was made.
For example, if the most recent change made to a contact was in MoxiEngage, select "Use This Version". However, if the most recent change made to that contact was in your email, select "Use Email Version".