, before those of us (like myself) who are about to get BL530 break out in a cold sweat, we need to know if your 12V battery might have been responsible - as @Harleyguy
I've posted this before: most of the original batteries were manufactured in the fall of 2011. They are near or at the end of their life. They should be replaced sooner rather than later.
Before anyone can blame the new software for the parking pawl issue, we need to see a pattern develop over time. There are others variables - like the condition of the battery, RDM, etc. - that may be factors.
So did Travis do anything else (like charge the 12V battery) before he re-flashed the HCU?