2014 Mazda6 Grand Touring with >130,000 miles. Well-maintained but now experiencing a new problem. When the engine and outside temperatures are hot, I'll put the car in PARK and shut off the car. The dashboard lights stay on and the screen reads Set Shift Lever to "P" as if I hadn't already. Brought the car to a professional, independent auto repair shop where they ran the diagnostics test and found nothing related to this problem. They got the engine up to temperature and, Murphy's Law, could not duplicate the issue (which is intermittent). Eventually, the car will fully shut itself off but we don't want to run down the battery by having the accessories on.
Has anyone experienced this issue and has a remedy?

 

Most likely the park position switch is at fault, same issue as the early CX-5s.

https://www.ebay.com.au/sch/i.html?_...fLoc=2&_sop=15

 

Don't know if this is the same or different but the "Park" electronics off sensors, not the shift lever assembly itself, failed and the whole shift lever assembly had to be replaced (it's all 1 unit including sensors) after about 195k miles. It cost about $750.

Took many months to diagnose, it kept the nav/radio screen and possibly dashboard lights on for a long periods, killing the battery. They even replaced the electronics on/ off actuator in the driver side door gratis just because they thought it was potentially the problem before diagnosing the actual problem. Went through two batteries with this.

 

Switch stuck. After a while the spring inside the switch pushes up and the lights go off. Put some WD40 on the sticky switch so when depressed, it pops up on its own immediately. Only replace if oiling it does not work. Spray from the gear stick bottom area if you can towards switch. Maybe access from underneath. The black parts on the white switch body photo are press down spring loaded switches. See photo you supplied.

 

This is the typical signs of a bad "Park Neutral Switch" or whatever name Mazda wants to call it for that specific model year. A professional can replace it in about an hour, model depending, but a DIY'er will struggle with the it, depending on their level of skill. The tear down to get to the module can be tricky.

In some models, this switch is built into the shifter, and require the replacement of the entire shift mechanism, so there's that too.