User information being deleted/changed

sharepoint2013
codeplex

#1
Some of my users seem to have their email address deleted and their full name has changed to their user name.

Any ideas why this may be happening?

#2
Do you have 'My Sites' setup? If the user is in My Sites, the profile information from My Sites will be copied over the local profile information for the site collection.

#3
I've just tested and yes it is that.

Thank you very much!