This is because the 'User' settings in the UserManagement say that 'User' manage the following user roles: (no roles are selected).
If you change the radio button here to 'All' it solves your problem (but might unearth other issues)
Samuel, If I understand you correctly, you have a datagrid showing columns of an entity, among which the datagrid shows the system.changedby and the standard csv-export button. Like this (I named Entity 'Entity' and attribute 'Attribute' due to lack of imagination):
Upon pressing "Export to CSV" you only get the values of 'Attribute'? That's weird, because in this case (having security Off) I get
Having security set to Demo/Prototype, and after changing the first object and pressing Export, I get the value as well:
Same when I switch to demo-user. So all looks fine. Where do you go wrong? Does Export to Excel give you the same problem?
Editted after Lukas Toft added his answer: I tried this in my model and he is absolutely right. Without the rights to manage users having a role that the current user is manager of, the changed&created attributes are no longer readable. You do however still get the values of each user that the current user does manage, including her own changes: