@ jose miguel,
According to the provided data operation was performed improper and Sigma Software hasn't performed any action to the phone, it have just reads information from it.
Try to Master Reset /Re-flash phone. Also, ensure that the phone's battery is fully charged.
Detailed manual on how to perform repair IMEI operation for A460 phone model available
here (IMEI Repair for ZTE Hexagon devices).
Best Regards
GSMServer team