"Charging did not finish/ Check Hybrid system/ Take to dealer" error

Hello folks,
Decided to hand over my 2013 PIP to my son who is using the Plugin piece heavily (every day and more). The car is in great shape with 148K miles.
Come this past Saturday morning, he was taking off for work and he get this error and could not get the car to "ready" to get in gear.
Did some online research and used my OBDII reader to see POD58 and really found nothing worthwhile.
Long story short, someone said they were able to fix an issue by simply unplugging the negative side of 12V and re-plug after 10 minutes. This worked, car went back to normal and its been 3 days. Sharing this experience because this site has been very useful and in case someone else can use this intel.
I will circle back if anything changes.