This is a weird one that we ran into here at Clear Technologies.

Backstory

Customer had planned prolonged power outage and after restoring power and booting the system it had lost it’s date. It is very rare because it can only occur on certain days of the year, roughly 6 of them when power is turned off at the end of one month and turned back on the next month, even if that’s just a couple hours apart. Truly a rare encounter for sure. Below is more details and fix to the problem.

 

https://www.ibm.com/support/pages/7063-cr1-hmc-incorrect-date-and-time-when-powered-back-after-being-powered-period-time