Check Hybrid System Diagnostic Help

I have a 2010 Prius IV model. In Jan-2017, I had the original hybrid battery replaced at 171,000+ miles with a rebuilt battery. I now have 281,000+ miles and just got the dreaded “Check Hybrid System” display. Prior to that message the battery system appeared to be operating normally from a charging and discharging perspective and I saw no major drop in my MPG after each tank of gas. I took it to Autozone and they were able to pull the P0A80 trouble code.
I tried an experiment where I removed the negative cable from the 12V battery overnight. When I reconnected the negative battery cable, the Prius appeared to be back to its normal state with no message or check engine light. I drove it around the neighborhood for approximately 20 minutes Without issues monitoring the hybrid battery being changed to capacity and power flowing both to the battery and from the battery to the electric motor. Once I powered off the car and powered it back on, the “Check Hybrid System” message and check engine lights came back on.
Does anybody have any troubleshooting techniques to determine if it is the hybrid battery or some other component of the hybrid system.
Any feedback anyone can provide will be greatly appreciated.