Update after ABB technician intervention:
The DSQC 663 unit was dead, swapped for a new one and all smooth sailing.
Tech guy confirmed there was nothing wrong with mains supply nor did we do anything wrong, sadly the dead unit will go back to ABB for repair and enter refurbishing cycle without any chance to know what was the actual failure.
The problem seems to have been bad luck.. maybe manufacturing defect or something, the robot is 107 hours only.
Luckily we were still 1 month under warranty left so that has not been as stingy as expected, ABB replaced the unit at no cost for us.