CMOS on this server (like most modern systems) no longer store the writable cmos settings in the RTC chip (which no longer exists) it's stored in one of the intel chips
if a cmos setting is not retained you either have the password clear jumper in the wrong position, or a bad battery, or a bad trace going from the battery to the chip that stores the cmos values, or a defective cmos section in the chip which stores the values note that the last one is highly unlikely as is the bad trace(s) to the chip
https://www.manualslib.com/manual/462221/Hp-Xw8200-Workstation-1-Gb-Ram.html?page=174