2015 Check Hybrid System No Codes

all,

My beloved 2015 Prius 4 just presented the "Check Hybrid System" Warning with all the associated dash lights. I took it to my local mechanic but they have NO clue and said they are at a loss because no error codes are presenting and the computer is "telling them nothing," with no other obvious issues from their diagnostics. I am now getting it towed to the dealership, woohoo.

Has anyone had experience with something this, seems like an annoying fluke or sensor issue? The car only has 55,000 miles and has only needed oil changes! The 12V battery is from 2020. I was driving on a slightly windy section of road under construction and so I slowed down like normal and followed the curves, then all of a sudden the car switched to this "fail-safe" mode and the warnings came on.

Thanks for any insights or suggestions!