Strange SOC, startup behavior on my 2002

In the last couple of weeks or so, I've experienced some odd SOC and startup behaviors.

Most notably, there have been 2 or 3 episodes where I was stuck in traffic and SOC would reach 100%, yet the engine would continue to run and charge the battery. In one case, I finally had to 'reboot' the car by completely shutting off the ignition and start up again as a fix.

in about the same time frame, I've also noticed that when turning the key to the Start position, the engine sometimes takes a 1/2 second or so to turn over, where it used to be instantaneous.

There have been no warning lights or messages of any kind as of yet, and the car has just over 70k.

 

Issue resolved. Turned out the auxiliary battery quit and is now being replaced.