Electronics can be glitchy. The other day, we had an 8AM departure in our G600 corporate jet. I fired up the plane at 7AM and was greeted with what seemed like 300 "blue" messages (non critical) and a handful of unusual amber messages. The brakes, landing gear, main entrance door, and other critical systems were all offline! Thank goodness it has great onboard diagnostics, I was able to look at each system, and see what was wrong. In each case, the CMC (maintenance computer) said "message logic, no LRU at fault" (LRU meaning component).
I have no idea what caused so many faults, but there was clearly one common theme, one key component (a DCN 'data concentration network') did not boot up correctly. By 8AM, I had shut down the plane, let it sit for 10 minutes, fired it back up, and all was well.
The suggestion above about low voltage is a very good one. It is likely that in my case, there was a low voltage condition upon APU start and the system simply did not boot up correctly.
Complex cars really are no different. I know we all expect the electronic systems to manage voltage properly. But everything from battery charge voltage to working system voltages are known to be a bit wonky on Accord Hybrids. Low bat V and especially a weak low capacity battery is very well known to cause a large number of strange issues. Including not being able to turn the car off or release the parking brake. I'd hate to be wrong, and send you down the wrong path, but as a first troubleshooting step, I'd simply purchase a new, high quality 12V battery, and charge it before installation.
EDIT: I also wanted to add that the Accord Hybrids (and other modern Honda's) don't seem to get good 12V battery life. This is probably due to the way Honda manages the charging, often letting the battery float at what we would consider lower than normal voltages.