@DaveN Thank you. I was also trying to talk to Xfinity agent to find out about Constant Guard. I am still waiting on cue. Meanwhile, I checked the Xfinity security page and found out followings (see screenshots).
Fix is nothing new: restart the device, update your software and pause your device, which I have done already. However, interesting findings are the indicated threats or attacks were made exactly the same day my Roon stopped working/started having this problem. Kind of puzzled…
I think Xfinity is not using Constant Guard any longer but replaced it with Xfinity xFi Advanced Security. I will have to confirm it with Xfinity. Still waiting…