User_Label will override the display label. The display label is a calculated attribute(as you can see in some classes xml definition and can be configured from CIT Manager Default Label tab) and it can be overridden with the value of "user_label". Customer should check who updates the user_label attribute.
This was added for BSM/RTSM. SIS topology will update the user label if no previous CI existed.
To aviod user updateing this field one can make the this invisable yo user. You may also want to consider adding another Attribute to the CI Type and use that field to add the values you were adding to User_label.
If this happens and user change the User_label you can use an enrichment to blank those items out.