Blinking PNRD lights on dash

The description sounds like the transmission is in limp mode do to an internal issue. That would be the reason for the blinking lights in those gears. The first thing to do would be to use a scan tool to pull any stored codes from the transmission and see what those show. It could be something like a bad solenoid pack or internal parts damage but the codes would be the first place to start. Unfortunately many of the places that were doing free scans have either stopped or restricted their activities and most wouldn't scan the transmission controls anyway. So you are left with buying a scan tool for a few hundred dollars or having a shop scan it and then getting a few opinions on what the issue is. This transmission doesn't have a dipstick so even checking the fluid color and condition isn't an easy thing to do without having a lift to get under it to access the fill/drain plug.
There was a recall on these for acceleration lag (NHTSA # 14V212000) in which they reprogrammed the transmission control module, but it didn't involve any of the lights flashing.

Hello, I'm Danny.

The first thing you should do is to perform a CAN scan to check all the systems on your car mostly including the transmission. Here is a tutorial showing what is involved for a CAN scan code check:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

After performing this get back to us with the code information and then we can properly diagnose the issue. Hope this helps and thanks again for using 2CarPros.