So, it looks like the issue is with HDMI authentication. I tuned to live TV and it said something about, HD Copy protection not working. I went to Tivo menu and saw "HDMI Status: Authenticating" it stayed like that for minutes...
Luckily I still had extra set of composite cables connected to TV. I unhooked HDMI and connected composite and Tivo went back to normal (no reboot). It is just as snappy as it was before.
No idea what happened, HDMI cable is less than a year old. Nothing was moved in months. No idea what happened, but I will try to replace HDMI cable see if it makes a difference.
Anyone else seen this behavior for HD Copy protection bugging down Tivo?