I had this exact problem with my TAF. Rebooted cold, warm, hot, attract mode, during MBs, completely randomly. Drove me flipping insane.
Mine was due to a combination of bad ribbon cables and a corrupt component on my MPU power board (U26 and U28). I systematically went through the entire pinWiki page on WPC resets to find it. That's why I always preach NO to the Kahr board. Do it right and never worry about it again, and even if it comes back years later, now you have the knowledge and experience to know what to fix and how to do it.
Here is my thread on what I did and what others have experienced with symptoms identical to yours. All cases from others within my thread: bad component on mpu board. As others are suggesting, replacing the IDC connectors with fresh female Molex connectors and swapping to brand new male head pins on the boards is a very solid thing to do too.
https://pinside.com/pinball/forum/topic/taf-resets-in-attract-mode
Good luck. I know it's frustrating as heck, but you'll get it!