Where does sharepoint take the domain name from?

Hi!

We have just completed an upgrade from 2010 to 2013 and experiencing a weird issue with the domain name somehow not being recognized.

For instance:

Our domain name is "domain.local"

when I go to a user's details I see the in the account column:

The "Name" column shows up just fine:

"domain\Username"

Our real issue is with alerts being sent from sharepoint,

in the SPS 2010 - we got alerts for every user changing it's picture, and the sharepoint changed the file name to the following form:

Domain_Username_LThumb.jpg has been changed 

but after the upgrade we recieve it in the following form:

temp_ABB55201username_LThumb.jpg has been added 

Any help will be much appreciated.

Thank you